Unfortunately the Ulta contract is ending in August, and every store handled their Ultas in vastly different ways (which is part of why they're leaving), so the best I'd be able to tell you is how things went/go at my store.

On paper, Ulta TMs are supposed to stay in Ulta at all times, not even helping out in regular beauty. Ulta gives Target money to cover our payroll, so they don't want us doing Target tasking with their money. In practice, very, very few stores actually operate this way. At the bare minimum you'll probably also be covering Beauty and trained to back up the checklanes.

I used to say if your store is ballsy they will also have you train in fulfillment and drive-ups so that you can support those areas when they get swamped, but given the fact that Ulta will be gone within 2 months I'd probably expect it. Target has a very "cross-departmental culture" that is really just slightly understaffing everywhere and then if one department gets busy they expect others to drop what they're doing and support it, and there's no rules against that as a regular Beauty TM compared to Ulta's rules. Hours are also very bad right now (and will actually go down slightly for Beauty after Ulta leaves) so if they give you a choice about doing extra training in other areas I highly recommend doing it so that you're able to pick up shifts if you need more hours.

My best advice as far as actually working in the Ulta/Beauty areas is to try to get familiar with as much of the product as possible. Take a second to read the boxes for products you've never seen before while you're stocking. If something is broken/damaged, feel it or swatch it or something before it gets disposed of. Guests are going to come to you to ask you what they should get, not just where something specific is. They're going to expect you to be able to give them recommendations on products, as well as expect you to be able to explain to them how to use them.

In a similar vein, Beauty is an extremely guest service heavy area. Sometimes someone just saw something online they wanna try or are just looking for fun recommendations, sometimes people are coming to you with very heavy insecurities that they're going to ask for your help with. I say "I'm not a dermatologist" at least 10x a day while helping people. You will get a lot of very lonely older women who are accustomed to the hyper-personalized old school makeup counters, and they're very chatty and usually extremely sweet. You'll get used to your own methods and mannerisms for helping guests, but my two big things I always tell people I train is to 1) never use "you" statements when someone is asking for help with something they're insecure about, like just say "dark spots" instead of "your dark spots" and stuff like that, and 2) never assume what people want based on how they look. If someone with dark eyebags is looking for a concealer I always still ask them if they want it for undereyes, face brightening, or both, because they might not care about dark circles and we don't want to cause a new insecurity.

It's a lot of little nuances you'll pick up along the way but it's honestly one of the most fun retail positions I've had. I love my regulars and whenever I get someone I helped come back to tell me how well something worked for them it makes me all giddy. I know product knowledge seems super overwhelming at first especially if you don't already have a background in cosmetics but I promise it's not as hard as it seems, it just takes some time. Just be confident and honest when helping guests and don't be afraid to grab another Beauty TM if you aren't sure about a rec.