Can you point out how to access the deep web?

Deepnet, Darknet, Deepweb, however way with a capital “D” it’s called, I’d like to access it, as I’ve got plenty enquiries pending that the tip of the ice berg couldn’t quite satisfy.
I read a specific software is needed, but I’m not sure if this is possible to use with Linux.
I’m not interested in whatever illegitimate activity might be on course there, so.. Be reassured you wouldn’t be helping a possible criminal get their stuff done. I simply have a strong sense of research.
Any suggestions?
Thank you