There's no such thing as a stupid question
First, you'll have to grab the trem source that your're trying to mod. Then you should try to compile it as-is and make sure that it fully works without any of your changes. You can read
here for more info on compiling on Ubuntu. You'll then have to make all the changes that you want and compile again. My guess is that most of your changes will be in tremulous.h, so look for that file and edit it after you have successfully compiled it.
Regards,
Kiwi
