hi im completely new to dnd. i have never played it before and want o play it with my friends. how does this work? is it all on this website?

Welcome to a wonderful new world ;)

You can start here, if you are a digital native.

The New Player Guide gives you a quick overview, and for further reading look at the basic rules.

I can also recommend getting a physical copy of the Essentials Kit. It has everything you need to start, including dice, rules, an adventure, dm screen, and reference cards. It also includes codes to claim the contents digitally here at DnDbeyond, and you get three more adventure modules digitally here, as well.

If you would like a guide on making your first character using the character builder, please see the link in my signature.

This website is an electronic rules reference and toolbox, like the character creator and encounter builder.

You will also need a tabletop (a virtual one like Roll20 if you can't / don't want to meet in person and will be playing online, or if you are meeting in person, the kitchen table works well), along with some polyhedral dice (4 sided, 6 sided, 8 sided, 10 sided, 12 sided, 20 sided).

And then someone will need to be the dungeon master, a combination storyteller and rules judge.

Its recommended to pick up a pre-made adventure when you are starting out, like the Essentials Kit or The Lost Mind of Phandelver.