I have no idea what you have read so far or need to read, it's something you just have to spend time yourself.
There's no get rich quick or quick entry into learning to be a domain seller. Domain selling is similar to many high end trading where you need to learn the markets and products (domains). There's a LOT to learn, so expect to spend months just picking up the basics, and in that time resist buying as you will buy worthless names (likely).