Interior

I haven't played doom or made any WADs for about 7 years. The last time I went into doom to make a WAD was around late 2015 to early 2016. After that I had went to college, recently finished college and I've been thinking of getting back into doom. However i don't know what's changed and what hasn't. I used Doombuilder and another program to insert custom textures into my maps. The issue is, I don't remember the name of that texture import program nor do I remember how to correctly import textures. If someone knows the name of it or has a download link I'd much appreciate it if you could link it in a reply. If anyone also has a tutorial on how to add custom textures that be much appreciated too. If someone could link a tutorial on 3D platforms as well I'd appreciate that. It's been ages since I last played. Even now I'm skeptical of trying to get back into doom because of how long I've been away. On a side note, I never released my WADs as they're sort of a artform to me. Even if I wanted to they've been lost to time. I uploaded most of my WADs to a private archive site at some point, something similiar to google drive. The website has since been shutdown or has changed its name