Hi, Rebecca. It's great that you are a responsible animal owner and want to do things right. I wish all new horse owners were so conscientious! Getting your first horse is a very exciting time. Be advised, though, that you are at the bottom of a learning curve that's higher and steeper than you can imagine.
I feel like I'm trying to stop a train wreck with a few meagre words, but here goes... Hopefully this is a nice, quiet, experienced horse; if so, there's less chance of you (and the horse) getting hurt or scared. Please listen to those who suggest you should board the horse for the first while. We can see pitfalls that you're unaware of.
A horse needs some sort of shelter, plenty of room to move around (a wild horse will do 25 miles in a day), companions (preferably other horses), as much good quality grass hay as he'll eat (I feed mine 4 times a day), free choice fresh clean water, and a salt block (not a blue one, though; those are for cattle), as well as regular hoof trims every 4-6 weeks. Grain or pellets is not necessary and I would actually advise against any concentrates if you are really going to keep the horse cooped up in such a small space. If your horse doesn't have adequate shelter or room to move, especially if exposed to driving rain, then a turnout blanket would be good. Never leave a horse unattended with the halter on.
I have to say that I would never, ever, consider keeping a horse in such a tiny area. Patandchickens has explained this very clearly, as she always does. If you insist on doing it, you can expect him to get bored, cramped, stiff joints, irritable, miserable, depressed, anxious, muscle sore etc. He will get opportunistic infections in his hooves (thrush, yeast etc). He may develop difficult habits like windsucking or weaving. He will also likely be higher than a kite when you do try to take him out, increasing the chance of accidents and injuries. It really is not fair to the horse and it's a risk you yourself can't afford at this early stage in your horse journey.
I know you mean well, but listen to the voices of experience. The boarding stable should be your first option and bringing him home at this time should be your last resort, not the other way around. And please, please, get regular lessons with a qualified instructor; after the care and comfort of the horse, that is the most important thing you can do, for both your sakes.
I wish I could make you understand what I and others here already know. We want the best for you and the horse. We'd like to support you in becoming a great horse owner as you embark into the incredibly wonderful and rewarding world of horsemanship. We know that horses are very complex and potentially dangerous animals, easily mistreated through wellmeaning ignorance, and a high level of competence is required. You will want to move up that learning curve as quickly as possible. Please take our advice. You'll thank us for it later.