I currently am in the process of figuring it out... But here's the breakdown.
A.) Do you currently have Developer Mode enabled on your chromebook?
B.) Do you have crouton (not folder, file) downloaded on your computer?
C.) Have you tried to run the code to open up crouton in your terminal?
If you don't know how to do some of this, click the link down below:
(Btw... I am not trying to play Doki Doki on Dev. mode... It's a pain to have to press [CTRL]+[D] every time shut the power on and off...)
This is probably the only way to do this. I suggest you uninstall every app that you can (other than chrome) on your chromebook before downloading crouton and starting it... *IMPORTANT!!!* Also, back up all of your files currently on a flash drive/google drive. All files left on your computer will be deleted when you enter Dev. Mode.
Link to 'How To' on installing ubuntu: https://lifehacker.com/how-to-install-linux-on-a-chromebook-and-unlock-its-ful-5...
This is the only way to do this.