In addition to the other post which links helpful previous posts I would also recommend this recent post by me which, specifically and in depth, deals with what a trench assault would actually look like.

I think this excellent post by /u/elos_ can answer any and all questions you might have about the front in WWI.

A human wave attack is a pejorative term for an attack by massed infantry on a defended enemy position, intended to overwhelm the defenders by sheer weight of numbers and regardless of inevitable high casualties (taken from the linked post).

As always, further discussion and new answers are welcome and appreciated.

P.s.: I hope it's okay to link to non-askhistorians posts.

EDIT:

Found some more stuff in our FAQ:

• We have all heard of the mass infantary charges in World War One, but what was the thought process behind them?

• I know nothing about WWI warfare.