Hi and Welcome to the community.
First, if this is your first experience with Unreal and C++, this is going to be a tough course. We would normally recommend one of the Blueprint courses first followed on by the Beginners C++ course (Don’t be mistaken by the name, it is beginners Unreal using C++) to get you familiar with the Unreal Engine and how the C++ works within the engine. If you’re not familiar with C++ at all, there is also a Foundation C++ course which focuses on the C++ language.
That aside, When you run from the command-line Add -LOG and -WINDOWED and you will get a log. If you are trying to use Steam it seems you may be missing a lot of the configuration and you may get an error. Most importantly in the log you’ll find an entry that states with online subsystem you are using.
Lastly, ensure the Steam OSS plugin is enabled in the plugins.
Once you’ve done this, give it a try and let me know how you get on. Note that you cannot run 2 copies using steam on the same computer as you need 2 separate accounts signed in.