I want to sell a few things on ebay but have some questions?

so i have a bedroom dresser and a wooden desk that i ant to put up for sale and maybe even a mattress and a box spring so that if it sells can use the money to put towards new ones that match, but i'm concerned about getting scammed and how to ship these things. I'm 18 so i know i can make an account but im scared to be overcharged or not get my money for the items,,,, can someone help me and explain how the process works? (no i have never used an online site like ebay or anything so the more info the better!)