Yes, do read more than one book.
Soaring in thermals is really hard to explain, maybe even impossible. I recall one dual flight with my syndicate partner, who was also an instructor. I was climbing us in a thermal, and after a bit he said "You're doing this all wrong - let me show you." So he took over, explained what he was doing, and the climb rate stayed exactly the same.
I then said "Let me show you how I do it" - same climb rate, but my explanation made no sense to him either.
When we tried each others' techniques (so far as we could understand them) the climb rate fell off. Go figure!
My CFI told me recently that he tells students to imagine that the thermal is a ping pong ball on top of a jet of water, and the pilots job is to fly the glider on top of the ping pong ball. Made sense to me, no idea how much it would help someone new to soaring.
FWIW, Ken Stewart's writing seems to work best for analytical types, Derek Piggott's for intuitive types. Read both.