So you'll want the basics: kennel, bowls, leash, collar, tags with your contact info in case the pup escapes (you can preorder these off Amazon with your info), basic grooming supplies, different toys, food, treats, etc.
Obedience training is very important with beagles. They are notoriously stubborn but extremely food motivated. So have some treats that are just for training, do 15 minute training sessions 3 times a day to help them learn a skill. Usually sit and lay down are pretty easy. They tend to relapse on housebreaking if you don't keep them engaged with learning. So just keep teaching stupid pet tricks.
They tend to really smarted and mature up at about a year. Before that they can be very high energy. Understand that dogs interpret any sort of touch as a reward, so you can be telling them "no" verbally, and if you have your hand on them, they think they're doing something positive. Toys are a reward, food is a reward. So understand how they are reacting to you and patterning what you do. My beagle was great with obedience training, but then when I tried to teach him once, it was a complete cluster. Turns out, he was used to me kneeling before we trained. Did that, boom, he was all ears. :D
Give your dog every opportunity to be successful. Assume there has been no training. I also establish boundaries with dogs, and I'm very specific about language. I ask them if they want to "take a break" for the bathroom, but go outside just to be outside. Off for furniture, but down to lay down, so that there's no confusion. I teach them in and out of rooms, the house, cars, on and off furniture, in and out of the kennel. That helps in the future if you break something glass, and you want them to stay away while you clean it up. Or if you have a baby and you want them out of the nursery. Realistically, you will yell at them to get out of the kitchen the most.
Unless they do something food aggressive or violent, I don't physically punish them. I just do a whole system of showing them how beneficial it is to keep me happy, and they go along with it because they are highly incentivized. I do recommend the following training video, I've been using it for years, it's a couple of bucks on Amazon to rent, but only like $6 to buy. It helps if you have one of those clicker trainers too.
https://www.amazon.com/Train-Your-Dog-Positive-Gentle/dp/B008WF9ZOC
Any other issues, just ask here or feel free to message me.