In my ASM folder I added a file called myCode.cpp
It was:

void nsub_02020354() {
}

And didn't work so I made it:

getCoin = 0x02020354;
void nsub_02020354() {
}

And still didn't work!
I pressed Run Make Clean between that, should I not have done that?

(Code is Dirbaios no coins example)

Oh, sorry when I hit run make and insert, then played the rom, I could still collect coins even though I added the nocoin code.
Oh, and text is still popping up when I hit the make and insert button, but then the window goes away so I thought that it was working...

Do any compilation errors pop up in the black screen when you click "Make and insert"?

If so, it means your code doesn't compile because there's something wrong with it, and it didn't even get inserted into the ROM.

Also the compilation errors tell you WHAT is wrong with your code, so read them!

Didnt you see what I said? the window goes away before I CAN read them.

Oh, it's okay then, if the window goes away automatically it means there are no compilation errors.

Then there's something wrong?

Is your code in a .cpp file in the source/ folder of the template? Also check it's .cpp, and not .cpp.txt! (Show the file extensions to make sure)

EDIT: Also check you're using the U rom.

oh, what? the src folder? I thought it was meant to be in the same folder as the rom.
alright, I will try that then