It depends on how long the event is.
Assuming that your first event isn't an Ironman, the transitionis likely to be open air and in public, with barely 2 foot of space allocated to you, your bike, and your kit.
If it's an indoor pool or heated outdoor pool, a wetsuit is frowned upon or banned. So you'll be piling out of the pool, running along a wet carpet to the bike, pulling on a top and number, hat, glasses and shoes.
Off the bike, swap the number to the front, go run.
Transition times count as part of the race, just like tyre changes at Formula One, and the best people practice them.
For your first one there's no need to buy kit because it's going to be a PB by default. So long as you have got a bike helmet with a CE mark (let's estimate that's one younger than 10 years old) and a roadworthy bike.
Don't get put off by the bling on display in the bike racks. The people with 6 grand bikes are almost certainly not 6 grand bikers. If they were they'd be sponsored.
I'm a noobie too, so I have an interest in the bottom end.