I want to add NOT, AND and other gates down to the STARRED section.. and how in world is this possible? People are mentioning that everything is possible with the default NAND, i get it but, the problem is, i see in youtube videos people have AND, OR, XOR buttons. How are they created?

When you save a chip, it automatically gets added to your starred section. Me, personally, I like to create a new collection called Logic gates, where I put all of my Logic gates in.

A NOT gate is basically just a NAND with a common input, an AND gate is a NAND gate plus NOT gate, an OR is when you invert both inputs of a NAND gate, and an XOR gate can be created with just 4 NAND gates connected in a specific way.