Extracting every class, method, property, modifier name from a different solution

What I want to do is: Making a Windows forms app that can load any kind of project/solution with it's projects inside and give me the names of classes, methods inside those classes etc etc. After that I want to save them into an XML file.

I am relatively new to C# and honestly have no idea where to start.

I tried looking into reflection but I somehow can only load one project inside a solution. Getting FileNotFoundException in another. And that's not even what I want. I tried looking into Roslyn but that's kinda a lot to grasp.

I need to load the entire solution to extract even the dependencies which "connects" the different projects.

I have no idea how to approach that. Any ideas here? I googled for 3 straight days, even looked at other projects in github, yet I couldn't find anything.