Newbie with pendulum ISO advice

A witch talked me into getting a pendulum yesterday ... haha. The pendulum i purchased is made out of rainbow moonstone (white labradorite) and was noted as being "a nice one" personality wise. She said it gave little sister vibes. The pendulum is being cleansed with the rest of my crystals (incense) and i've been asking it a couple basic questions to feel it out. Not sure if i'm doing this right but it's a bit draining to use... I've had a headache all day.

This whole process has got me thinking about how people incorporate pendulums into their craft. I am decidedly NOT a witch (the pendulum also said i wasn't cut out to be one *sigh*) but i do work with tarot cards, meditate with myself, and *feel the earth* from time to time. All of this is more or less self-taught - maybe I should read a book lol. Nevertheless, i feel myself being drawn into spellwork. How do you use pendulums if at all? What about crystals? Am i able to use pendulums to identify guides? What do pendulums do for spells? Am i in the right subreddit?

I would love to know how these tools have aided your path!