There is an Action Bar at bottom of the User interface. Each class starts with some skills. Every few levels, you will unlock new skills specific to your character class, these can be learned from your Class trainer. You will be introduced to one of these NPCs during one of the first few quests you complete in your starting zone, but they can also be found in many towns and each of your Faction's cities.
This is definitely why we do a beta test. We can also do things like reset the realm at a busy time like 4:30pm PDT to try and find the source of a certain issue where a crocolisk is losing it’s brain due to how multiple processes are interacting and mirroring code to form a cohesive world. There were similar types of issues like this back in 2004 but we wanted to try and resolve this one before the weekend for the folks who are testing.
You can’t go wrong with a mage. In fact, Mage was the most popular class in World of Warcraft: Classic due to their ability to farm with ease. Back in the day, the player majority even leveled mages as alts in order to gather gold quickly. In addition to their monstrous ranged DPS, mages also have tons of useful utility. As a mage, you’ll be able to conjure food and water, place portals to the major cities, and even earn gold from doing so.