Hello,
Film has a backing as well as a sensitive emulsion. This does several things. It helps to prevent the film curving when the emulsion side is wetted and swells. I think we can see the value of this. Some backings may assist retouching, although Photoshop has probably made this obsolete.
It also helps to prevent light from being reflected from the back of the film, after it's passed through the emulsion and re-exposing the film with this surplus light. It's called an anti-halation backing because it prevents haloes being created around bright detail. It was first used on glass plates, which had no need to prevent curving.
There are also stains and dyes in the film, to optimise it in various ways. I pre-soak my film and the soaking solution comes out green. Fixing is supposed to remove all of this and some films need longer than others.
The sensitive emulsion side should face the solutions. Ideally, neither side would touch anything.
In case you've missed it (and I apologise if you know) when a sheet of film is held up with the short side at the top, the sensitive side is facing you if the notches are in the top right-hand corner. Obviously, bottom left will be the same, but we generally load film into the holders so that the notched end goes in last and can be felt and checked easily, if the need arises.