Rings?

[Luca_K04]

I'm at the Gold Saucer and during the journey I looted various rings like "talisman", "white cap", "power wrist"... they seems raise stats and protect but I don't understand how to use them.

[Sheff]

They are accessories. Equip them where you equip your weapons and armour.

[Luca_K04]

good god, I didn't noticing the Accessiores tab....

[Xengre]

Also worth noting the best accessories tend to be those preventing status effects, notably the Ribbon which you can get 3 of in the game (more if you are at end of game from Tonberry but otherwise 3 normal ones found across the game). These stop all status effects and are a reoccurring item in the franchise. Aside from anti-status effect the next best to consider are those that heal from some elements (like a certain water absorption ring found just before a certain major story boss so that dying doesn't ruin a certain crazy story moment, as you literally can't die with that ring against the boss lol)

The other is Tetra Elemental which causes most elements to heal you but its kind of pointless in this game and inferior to Ribbon, esp as your evasion stat climbs.

There is one oddball super hidden accessory to be aware of which is the Cursed Ring which grants an immense stat boost in exchange for once per battle at the start having the death timer put above that character's head. Notably its great on a certain Tifa setup with a certain weapon to get absurd dmg early but kind of pointless because Beta/Magic Breath are mega OP Enemy Skill and Cloud's limit break 3/4 exists.

While you are in the Golden Saucer area drop by one of the nearby forests. You can actually do this at other forests such as the Fort Condor one but the one you are at is fine, too. Run around there repeatedly fighting until a certain very "special" enemy shows up you definitely don't want to miss Yuffie, a hidden party member just like Vincent. They have some minor side events but aren't a major part of the main story though they have minor dialogue/etc. if you do get them. Note don't listen to Yuffie if you find her or you have to repeat the process again... If she says save or use your menu do not do this. Choose the options that blow her off and have you and your party LEAVE HER. She will join you. Any other action will trick you and she will flee.