The late Craig Luebben has written some good books to help get someone going with learning about traditional climbing. For example, ...
https://www.rei.com/product/758923/rock-climbing-anchors-a-comprehensive-guide?CAWELAID=120217890000837454&CAGPSPN=pla&CAAGID=16032967240&CATCI=aud-87986356584:pla-70911769600&cm_mmc=PLA_Google|404_6099|7589230015|none|813eb985-3714-4a33-a1de-d4eb3ff1bb26|aud-87986356584:pla-70911769600&lsft=cm_mmc:PLA_Google_LIA|404_6099|7589230015|none|813eb985-3714-4a33-a1de-d4eb3ff1bb26|aud-87986356584:pla-70911769600&gclid=CM-i2c3629QCFQyoaQodKBAJCA
Finding a "mentor" is rarely possible. Most climbers that are really good don't want to climb with (in their mind: baby-sit) a novice; they want to climb with those at or above their own level. And if you do get to climb with someone more experienced, and then accidentally put on what is commonly referred to as a "sh*t-show", they'll never climb with you again. Say good-bye to that partner forever.
To try to break into trad-climbing, I've just read the books, practiced at ground level, then gave it a try with a partner at or below my own level, hoping for the best. Every now and then you may be able to go out with a more experienced person who can follow your lead and check your placements and tell you what they did or didn't like about how you led a pitch. This is very helpful.
If you're willing to pay tons of money, you can also hire an AMGA certified guide to check your work or show you some stuff. They're not always good teachers, though; and you don't always get what you pay for. All the books will tell you that you're risking too much if you try to break into trad-climbing with anyone less than an AMGA certified partner. But if everyone followed that advice, then only the super rich could ever learn the trade.
In my opinion, the problem solving principles, the knots, the rigging, inspection of the rock on a small and large scale, intuition about potential forces, anchor building, etc., is the more accessible part of climbing. It's a person's ability to move their body up the rock face (i.e., the actual climbing part of climbing) that is the barrier to entry. Sure, anchor-building is the foundation, but in many situations, your primary and only real protection is your own ability to climb, and a fall is unacceptable until you reach your next placement, even if you're doing everything right and being as conservative as possible with the protection system. Some climbs just don't offer all the protection placements you'd like them to have. There's also some skill in identifying potential placements. You would never want to skip a placement just because you didn't recognize it.
Those are my thoughts on the matter, but I have to admit that my trad-climbing ability and experience is quite limited. Now that I've discredited myself, you can forget everything I've just said. Ha!