How to able simple visitor to post an article

Hello,
(I’m french, sorry for my english)

I’m trying to make a website where everyone can send a post message, and everyone can comment the post.

I don’t want plugin… I want to know how to do that.

I’ve got an idea :
Make a form, and then the value will be stock in the DB with SQL query. But i never used WPDB… So i’m affraid.

Short, i want to put the Backoffice on the Front Office. But i want to accept or refuse new post.

I want to create a Custom post type. buti don’t know how to put data in the db with simple wp basic function

THANKS A LOT.