Important considerations:
Plenty of coop and run space. Absolute minimum: 4 s.f. in the coop and 10 s.f. in the run per bird. I recommend that you start with twice that amount! B/C you never know when you'll just "HAVE" to add some new chickens! What will you do with any accidental roosters? What will you do when your hens stop laying? While the keep them forever idea is what some folks choose, that can get to be pretty expensive to be feeding a non/productive flock year after year. Many chicken keepers keep a rotating flock: bring in a few new chicks every year, and cull the older, non/productive birds.
Coop safety: Plenty of ventilation and light. All openings covered with 1/2" hardware cloth. Chicken wire is designed to keep chickens in, but is not at all predator proof. Run: IMO essential, even if you plan to free range. There will be times when it's a must to keep them behind a fence: predator visitation, training them to the nest box, flock deciding to go ranging too far from home. Roosts: at least 10 - 12" length/per bird. Best to be on the wide side so those toes don't get frost bit. 2 x 4 on the flat works well. Roosts need to be far enough from the back wall so the chicken's tails don't touch the wall. Need to have enough ceiling height so chickens can perch (ideally) without reaching the ceiling. The little prefab coops often don't allow enough height to allow chickens to roost, and have good ventilation.
Choice of bird: For very cold areas, look for birds with small combs (rose, pea). Henderson's chicken breeds chart is a good place to start looking at all of the excellent options available to you. Decide what is important to you: Temperament, egg production, egg size, egg color, broody/never broody, cold/heat tolerance, color preference. My preference: small comb, colorful egg basket, cold tolerant. I love a mixed flock. I love Dominique and EE. Other folks choose to have birds of all one breed.
How to start your flock:
If you're going to start with chicks, you'll need a brooder. They grow fast. Plan to give them 1 s.f./chick. While a heat lamp is the standard fare, a more natural method is to use a heating pad cave that more closely mimics the heat produced by a broody hen.
https://www.backyardchickens.com/a/yes-you-certainly-can-brood-chicks-outdoors
Started birds: will cost more, but will produce a laying flock faster. Generally, they will be between 8 - 16 weeks old. You should be guaranteed that they will all be pullets. Older birds: some flocksters will be removing their older birds or culling their flock. Sometimes someone will be getting rid of all of their poultry for one reason or an other. If you go this route, it's best to have someone go with you to see the birds to help you make an informed decision. You don't want to pay good money to buy someone else's problem birds. There are good bargains, but... buyer beware!
Finally, don't rule out the option of starting your flock with fertile eggs! That's an incredible learning experience, but only if you're the adventuresome sort, and willing to accept the possibility of a failed hatch. You can purchase an incubator, borrow one, or make one! If you have the confidence to re-wire a lamp (given good instructions) you can make a very good incubator for a fraction of the cost of buying a so-so incubator! I recommend that if you go this route, you avoid shipped eggs, and get your eggs locally.
No matter how you start your flock, I recommend that you get all of your birds from the same source and at the same time. The risk of introducing disease or external parasites is very real when mixing and matching older birds from different sources. Also, it's difficult to integrate new birds into an existing flock.
I wish you the best with your adventure! Happy learning!!!