what and where i can have custom things ( like for exemple CustomText )

is problematiic because i would like to run my mod and my vehicle pack , but have told me that i need CustomText for exemple and other and i don't know where it is and how did it get there ?

Hacks should automatically get loaded if a mod requires them. You have to edit Meta.ini in your mod folder and add "RequiredHack=NameOfHack". There are different hack and these have different functionalities, i recomend Gordon's tutorials to understand better the mod making