and then there is also the difference between sram (static) and dram (dynamic). sram is usually made with logic circuits, like in the links above. dram is simpler and usually made with cheaper components, such as a single capacitor and transistor per bit. but since capacitors leak over time, dram has to be continually refreshed (read and re-written)
understanding flip-flops and latches is the beginning to understanding computer memory at a low level.
the beginning to my understanding was the book "Code" by Charles Petzold.
more recently, I discovered a series of instructional videos on building an 8-bit breadboard computer using simple logic gates and IC chips, by Ben Eater. He both explains and demonstrates the basic concepts while constructing the basic components of a small working computer. links to his youtube videos from here: https://eater.net/