David X. Newton just put out a video detailing how many of the sections of the map work, which I can totally recommend watching. There was plenty of stuff I didn't notice, haha

If you haven't played it, though, definitely do that instead of watching this!

Download GZDoom, put a copy of DOOM2.WAD (from Doom 2, as its name implies. Obtain this however you like.) in its folder, and drag myhouse.pk3 (not myhouse.wad) onto the GZDoom app to run it

@lexyeevee has an excellent hintguide here if you get stuck!