Steady weapons are for theorycrafting, since they have no damage range.
PvP gear is obtained through glory chests, rank chests, and the mystic forge. All gear besides the amulets and gems are statless. Gems and amulets (runes + sigils as well) can be obtained for free.
When you rank up, you get a rank chest. You can also spend glory on a glory vendor for a glory chest, assuming you already have the rank required to do so (they go like, Rank 1, Rank 10, Rank 20, ect.). Each 10 ranks has a new tier of gear, which these chests contain in addition to other things like Finisher animation changes and boosts. If you receive an item you don't want from the chest, you can salvage it, and then with four of them (I don't know the exact details for this stuff, I think it's the type of armor you want, what rank you want it, and then two things of dust or something) you can put them in the mystic forge and get a new item.
As far as I know, all armor/weapon skins can be obtained in sPvP.
So in short:
PvP progression is cosmetic, and does not have an effect on your performance.
PvP gear is obtained through chests. These chests can be bought or obtained for free every rank.
You can salvage PvP gear to put into the mystic forge, and obtain a new piece of PvP gear.
There is also a PvP locker which stores all your PvP items, like a bank.