So I'm new to 3d printing,

That page that I gave you a link to said ‘BOARD_MKS_BASE’ but that is not the board you selected.

Huh what? You selected two different boards in two different pictures. I recommend a simple web search when in doubt. I just looked for ‘mks gen L firmware setting’ real quick, check out a link and looked for ‘firmware’ on the page and I found it.

@NathanielStenzel thanks for the nudge in the right direction!

@DayRider76 did you finally get it compiled?

@NathanielStenzel not yet, but I don’t quit!

@DayRider76 I can try to boot up my laptop and send you the settings that I used for my MKS Base 1.6 later. We should have the same board settings. Mine just has the stepper drivers built in while you have more freedom of choice. I think that is all the difference there is between our boards. Hmmm…maybe a different serial port chip too.

It seems I need to use MOTHERBOARD BOARD_MKS_13. Maybe I could use the BOARD_MKS_BASE that the one person recommended for your board, but I did not try. There were a few recommendations for my board. The arduiono IDE says board “Arduino/Genuino Mega or Mega 2560” and processor “ATmega 2560 (Mega 2560)” and programmer “AVRISP mkII”. I had to actually boot up my laptop to get the settings for you and previous posts were from memory.

I imagine your next stumbling block will be the display. With a little web search, you may figure that one out easily enough.

@NathanielStenzel I’m getting closer, I only have one error now, saying the system cannot find the file specified. Error compiling for board Arduino/Genuino Mega or Mega 2560

Maybe you accidentally modified an #include line?

@NathanielStenzel it now says
Assembler messages:
Fatal errer: can’t create sketch/marlin.ino.opp.o: Permission denied
Exit status 1
Error compiling for board arduino/Genuino Mega or Mega 2560

Linux, Windows or other? If Linux, were you running the arduino IDE as root previously and changed file permissions? I do not know the .opp.o deal. Maybe the arduino IDE makes such a temp file (shrugs) If in Linux, make sure to be a member of the “wheel” group (as recalled from memory… hopefully correctly) so that you have port access without being root.

Windows 10

I only use that OS when my mom complains about computer issues so I really can’t help you there.