Hello there, and welcome!
Yes, there are a bunch of tutorials on the site, and you can check them out here!

I can recommend a few that you'll most likely need through your modding journey:
1) Creating:

• Missions
  
• Cars
  
• Movies (Or FMV's/Cutscenes)

2) Adding:

• Music
  
• Dialogue

3) Advanced:

• Level swapping

I also recommend you download this mod template and check @The Butter Apple 's YouTube channel, he has a ton of helpful tutorials.
Good luck with your stuff!

• Missions
  
• Cars
  
• Movies (Or FMV's/Cutscenes)

• Music
  
• Dialogue

• Level swapping