Just set-up (JACK)hammer editor and play 1998 virtual legos, Wadmaker with (png files less than x512 and dividable by the number 16) will let you paint your legos custom colors from the original play set. From there you can look at the various entities and think about what cool shit you want to attempt to make in each boxed lego room, you will look at the wiki and TWHL wiki and when stuff doesn't work you can seek advice from the old boomer sages in the discord. Goldsrc is a lot more interactive than quake and all of its modern day clones, you can do a lot of cool stuff but you need to understand that the stuff you do in Goldsrc is all smoke in mirrors. It requires creativity and tinkering.
Looking at your post history, you have gone from talking about releasing a mod in christmas, to not releasing it, and now you are asking people to make a huge mod for you, the idea for your large mod is vague and has already been done before. The old timers here will not be interested, furthermore you aren't really offering any help for this mod, even texturing wads and sound design by you're own admission you "might need help with".
So my question for you is this. What is your motive? I got into goldsrc because I wanted to make brush based levels, I struggle to wrap my head around programming so its nice to play with something that has a bunch of built in entities for me to play with, goldsrc has its problems (mostly a lack of modern cross platform support for tools) but its fun to play with and learn.
If you don't want to make your own custom brush based maps, model anything, make custom scripts/entities via coding. Just what exactly is your motive for even getting into goldsrc?