Are there any tutorials for making underwater environments?

I’ve tried to make underwater environments a couple of times with certain turorials, but I got completely lost.
Can someone help me out?

Any help is appreciated.

i made an under water enviroments a few months ago…

Old, but maybe useful:

ah, thanks.

The bongo’s environment one was one of the tutorials i got confused with.
I got lost when I was to upload a “t marble” texture from a plugin along with a caustic image. I tried but I don’t think I did it right.