Yeapp of course, just follow the readme and/or the comments in the sourcecode . You just need to alter some text and then compile it (create an exe, "button" is called compile). If you want I can make it for you, you will then only need to see what changes I've done to easily understand what to do. Just give me the pokes and window name then.
However if you don't want the trainer to be 500kb it's a good idea to compress it. I can give you a tool called UPX, there you only need to find the exe and then press the compress button inside UPX (almost like winRAR however UPX doesn't archive the exe). The trainer will then be at 200kb or something like that.