You should check out these videos, one of them might give you an understanding!

- https://www.youtube.com/watch?v=JhHMJCUmq28 | Quantum Computers Explained - https://www.youtube.com/watch?v=IrbJYsep45E | The Mathematics of Quantum Computers - https://www.youtube.com/watch?v=wUwZZaI5u0c | Hacking at Quantum Speed with Shor's Algorithm - https://www.youtube.com/playlist?list=PL1826E60FD05B44E4 | A series by the author of the standard textbook

These are videos I particularly like!

Quantum Computation and Quantum Information, a.k.a "Mike and Ike" is the authoritative textbook in the field. It also happens to be very readable and beginner friendly. It's well worth reading the introduction to QC in the first twelve pages and skimming the first sixty. And the rest, as time/interest permits.

I recommend the textbook Quantum Computing for Computer Scientists.

This sounds snide, but please believe me my intention is to be helpful.

Have you considered instead raising your level? The relevant topic, as stated in the comment, is linear algebra.