I can't get my 2020 Macbook Air to run a Diagnostic Test.

I spilled coffee on my 2020 Macbook Air. I quickly turned it over into the 'tent' position and then turned it off when I read that was the best thing to do. It air dried for 3 days, the first day with a fan pointed underneath it. It's been 2 days since I've turned it on, and everything has been working great besides some sticky keys. But today I was on a webpage that I am often on for school and the fan kicked on, which has never happened with that website before. I read something about checking the hardware and running a diagnostic test to see if there is something wrong, so I followed the steps for Apple Silicon from Apple's website: Use Apple Diagnostics to test your Mac – Apple Support (UK)

When I turn on my Mac holding down the power button, the apple will show up with that 'waking up' sound, and then I hear a click-click, and it shuts off. I've tried this about 10 times with the same thing. Then I tried the Intel processor steps just to make sure I wasn't doing the wrong thing, and that didn't work either, my Mac just went to the log-in. Can anyone help me understand what I may be doing wrong, or if this has to do with the coffee spill(in which case I need to get the computer looked at). I am a college student with basically no money, so I want to try everything I can before having to pay for someone to fix it. Thank you.