Switching music?

I’ve only found tutorials to adding completely new soundtracks could someone point me in the direction to a tutorial for instance that would help swap the music from l7m2 to l1m5?

Starting out, you'll want to use the RMS Builder to get XML versions of L1 and L7's files.
Then you open l7_music.xml and search the document for this area.

<Region Name="M2_main_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicRepeatEvent>
			<StreamEvent Name="UFO_Main" />
		</LogicRepeatEvent>
	</Layer>
</Region>
<Region Name="M2_end_Pos_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicRepeatEvent Times="1">
			<StreamEvent Name="UFO_End_Pos" />
		</LogicRepeatEvent>
	</Layer>
</Region>
<Region Name="M2_end_Neg_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicRepeatEvent Times="1">
			<StreamEvent Name="UFO_End_Neg" />
		</LogicRepeatEvent>
	</Layer>
</Region>
<Region Name="M2_end_Sus_region" ExitRegion="OF_explore_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicRepeatEvent Times="1">
			<StreamEvent Name="UFO_End_Sus" />
		</LogicRepeatEvent>
	</Layer>
</Region>

You'll then want to find the section where those stream events are defined.

<Stream Name="UFO_Main" RSDFile="UFO_Main" Streamed="true" TempoTrack="93 4/4" TempoTrackStartBeat="1" />
<Stream Name="UFO_End_Pos" RSDFile="UFO_End_Pos_b4" Streamed="true" TempoTrack="93 4/4" TempoTrackStartBeat="1" />
<Stream Name="UFO_End_Neg" RSDFile="UFO_End_Neg_b4" Streamed="true" TempoTrack="93 4/4" TempoTrackStartBeat="1" />
<Stream Name="UFO_End_Sus" RSDFile="UFO_End_Sus_b4" Streamed="true" TempoTrack="93 4/4" TempoTrackStartBeat="1" />

After that, continue your search for the RSD files themselves.

<RSDFile FileName="UFO_Main" Size="16848500" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
<RSDFile FileName="UFO_End_Pos_b4" Size="406660" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
<RSDFile FileName="UFO_End_Neg_b4" Size="669992" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
<RSDFile FileName="UFO_End_Sus_b4" Size="552956" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />

After you've copied these into a separate document, you'll want to open l1_music.xml and systematically add these lines where they each belong. Instead of simply replacing the regions, however, it may be better to find the regions for L1M5 and instead replace the stream events. Once you've done this, drag l1_music.xml onto the RMS Builder, then pop it into the appropriate folder and try it out.

Im not sure where i went wrong i was experimenting with l4m4 and i copied each of these over the original orch_chase things

<RSDFile FileName="Otto_Chase" Size="17462780" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
	<RSDFile FileName="Otto_Chase_End_Pos1" Size="400696" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
	<RSDFile FileName="Otto_Chase_End_Neg1" Size="437296" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />
	<RSDFile FileName="Otto_Chase_End_Sus1" Size="564352" AudioFormatEncoding="PCM" AudioFormatChannels="2" AudioFormatBitResolution="16" AudioFormatSamplingRate="24000" />

<Stream Name="Otto_Chase" RSDFile="Otto_Chase" Streamed="true" TempoTrack="170 4/4" TempoTrackStartBeat="1" />
	<Stream Name="Otto_Chase_End_Pos1" RSDFile="Otto_Chase_End_Pos1" Streamed="true" TempoTrack="170 4/4" TempoTrackStartBeat="1" />
	<Stream Name="Otto_Chase_End_Neg1" RSDFile="Otto_Chase_End_Neg1" Streamed="true" TempoTrack="170 4/4" TempoTrackStartBeat="1" />
	<Stream Name="Otto_Chase_End_Sus1" RSDFile="Otto_Chase_End_Sus1" Streamed="true" TempoTrack="170 4/4" TempoTrackStartBeat="1" />

<Region Name="M4_Main_region" Volume="1">
		<Layer Name="music" Constant="true" Volume="1">
			<LogicRepeatEvent>
				<StreamEvent Name="Otto_Chase" />
			</LogicRepeatEvent>
		</Layer>
	</Region>
	<Region Name="M4_end_Pos_region" Volume="1">
		<Layer Name="music" Constant="true" Volume="0.77">
			<LogicRepeatEvent Times="1">
				<StreamEvent Name="Otto_Chase_End_Pos1" />
			</LogicRepeatEvent>
		</Layer>
	</Region>
	<Region Name="M4_end_Neg_region" Volume="1">
		<Layer Name="music" Constant="true" Volume="0.77">
			<LogicRepeatEvent Times="1">
				<StreamEvent Name="Otto_Chase_End_Neg1" />
			</LogicRepeatEvent>
		</Layer>
	</Region>
	<Region Name="M4_end_Sus_region" ExitRegion="OF_explore_region" Volume="1">
		<Layer Name="music" Constant="true" Volume="0.77">
			<LogicRepeatEvent Times="1">
				<StreamEvent Name="Otto_Chase_End_Sus1" />
			</LogicRepeatEvent>
		</Layer>
	</Region>

(I still honestly have no clue what im doing and have not succesfully replaced them yet)
EDIT:it always crashes

"copied each of these over the original orch_chase things"
I should have said this in my original response; with RSD file information, you should add rather than replace. For example, L4M3 and L4M7 both use Marge_Mission01b_Main.rsd, so replacing the RSD file information when modifying music in M3 would break M7 and vice versa. Replacing won't cause you any trouble in L4M4, but keep it in mind going forward.

This image is no longer available because of changes to Discord's CDN what caused this?

I'm not entirely sure if this is it, but I would recommend you remove those blank lines you've got there.

Adding a new post just so I'm sure you see this, those two regions should appear as follows.

<Region Name="Sunday_Drive_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicRepeatEvent>
			<StreamEvent Name="Marge_Mission01b_Main" />
		</LogicRepeatEvent>
	</Layer>
</Region>
<Region Name="Sunday_Drive_Sus_region" ExitRegion="OF_explore_region" Volume="1">
	<Layer Name="l" Constant="true" Volume="1">
		<LogicOrEvent>
			<StreamEvent Name="Marge_Mission01b_End_Neg" />
			<StreamEvent Name="Marge_Mission01b_End_Pos" />
			<StreamEvent Name="Marge_Mission01b_End_Sus1" />
			<StreamEvent Name="Marge_Mission01b_End_Sus2" />
		</LogicOrEvent>
	</Layer>
</Region>

You lost the opening of the repeat and or events which will break your music.

Also still remove the blank lines probably.

Ah, Thanks