So the Manderville Golden Saucer is side content. As a quasi-casino, it exists primarily as a home to mini-games. The story never really requires you to engage with any of the mini-games, but it can be a great diversion. Playing the games will net you a special currency MGP(manderville gold points i think), and you can spend those on a variety of cosmetic rewards. They have outfits, emotes, minions, music rolls, and mounts among other things.

If you play around in the settings(i think its under character config), there are a few ways you can configure your hotbars. It might feel a little slow since you arent used to it, but a lot of high level players do so on controller. The game was designed with compatibility in mind, so it really does work well for any role. I play keyboard and mouse, so i wont include specific advice that might be wrong.

There are well over a hundred mounts available in game(and another dozen or two on the cash shop), but until you do the quest that MistakeNot mentioned you wont be able to use any of them. Once the feature is unlocked via the quest, any mount you received in any other way becomes available. Aside from the first chocobo from that quest, the Gold Saucer has a few easy mounts. You can also check the achievement certificate vendor(his name is Jonathas and he stands near the waterfall in gridania). You probly havent earned a ton of certs yet as a newer player, but as they accumulate youll have your choice from his inventory too.