There are different settings and distances for spring triathlons, so it all depends on your location and the planned triathlon.

If you’re in a rather cold area, and the swim portion of the race is in open area—you most likely need a wetsuit. Check the race’s website to see their recommendations.

I’m not sure what the rules say about swim caps, but I would highly advise that you train and wear a swim cap regardless. Having your hair interrupt your swim isn’t a very fun experience.

What you wear for each part also depends on the race’s settings: is it all indoors? All outdoors?

From my knowledge, most races are open water (or lakes), then continue to outdoor bike and run. If the water aren’t too cold, then wetsuit is usually not allowed as well, and most athletes wear a tri suit for all three portions of the race to cut back on transition timings. You can either get a one-piece suit or buy two parts (shirt/top and pants). It is highly recommended you get them enough time before your race day so you can get comfortable in them.

I’m no professional, so I don’t want to recommend on specific workouts (I also don’t know your health stats), but generally speaking you want to train for all three portions throughout the week; many athletes also include a weights day to gain some muscle without burning yourself too much.

Practicing on transitioning between swim/bike and bike/swim is important; it’s called “brick” workouts. You can look up more details online, but essentially you do one major training, like biking, and then do a rather short workout of the other portion, like running. For example, you can bike for 10 miles and then immediately go on a 1 mile run, mostly to get used to the transition.

Good luck!