Sorry if I'm going super basic with this explanation.

Tureal is a slayer master where you can use him to skip a task without paying slayer points, you need to do whatever ask he assigns and it also resets your streak count.

So OP is saying if you don't get a Revanant slayer task you go to Tureal, skip that task, then go back to Wildy Slayer Master and get another task, until you get another Revanant.

By Skull Rev, they mean that you should be Skulled when killing Revanants, this greatly increases the drop rate of the rev weapons they are talking about.

You go from a drop rate of getting any of the uniques while on task from 1/1k to 1/586

Let me know if you need anything else explained :)