About the user initialize

Hello everyone, I am new to web3.0. I have struggled with the official introductory manual for three days and have a general impression of the whole system. I am still confused about the details of the modules. I want to know how to connect to ic-cdk and use rust to implement user additions, deletions, changes, and inquiries? How to initialize a batch of local users? I don’t know what’s going on with the Principal? Ask for guidance. I wondering if there are specific learning resources for me to use rust to implement user login and connect their wallets.