i went on to its github
https://github.com/lvlann/PokeFilename/new/master?filename=.github%2Fworkflows%2Fdotnet.yml&workflow_template=ci%2Fdotnet
right side it states "Setup .NET Core SDK"
under it it says "Installation Copy and paste the following snippet into your .yml file."
I copied the snippet and opened "azure-pipelines" which is the only yml file with notepad and pasted the snippet at the bottom and saved it.
tried opening the sln again, but it gave me the same error.
setup .net core sdk was the only thing closest to what u mentioned.
not that its not obvious, but my Major is not computers, its Aviation lol. But i LOVE to learn anything and everything new. That being said, I dont intend to be annoying just trying trying to learn something entirely new which might even help someone else in the future. I really hope you guys dont mind taking the time out of your schedule to help me figure this out, and I really really appreciate it.