You mean grow? As in what do I personally do?

I plant it usually between Nov 1 and Dec 15 (I'm in zone 8a). Most people say 1-2 weeks after the first hard frost and for me that would be around Oct 15 - I usually go later only because I'm busy since our markets run until the end of Oct.

Just break up a bulb and plant each clove pointy end up about 1" deep and 4-6" apart in any direction in moderately fertile soil with good tilth (ie good drainage - not too heavy clay, ideally). I don't grow this for market any more (weirdly, it was never high demand) and just put it in a raised bed. I leave the soil bare in winter to absorb heat and in my climate don't worry about frost protection but if you are in a colder climate you should plant deeper - even 3-4" deep in zone 3 and maybe even mulch. But it's very frost hardy.

I'll typically weed a couple times before mulching. Once temps start to rise in spring I'll cut fresh grass with a hand scythe and use that as mulch to reduce moisture loss and keep soil temps as cool as possible. Obviously this also helps keep weeds down - garlic doesn't like competition. If you are growing hard-neck varieties, which you absolutely should, then cut the scapes before they get tough. Garlic scape pesto is the bomb - I make a huge batch and freeze it.

I'll stop watering once I start to see bottom leaves browning (as temps rise the plants stop growing) and usually harvest once about 2/3 of the plant is brown - typically July for me. This varies a lot by conditions and variety - digging one up to see is a good idea. You can eat them "green" no problem.

I don't like to cure in the soil and prefer to harvest and let them cure on a drying rack in a shaded but breezy place. Properly cured and stored even hard neck varieties typically last 8-9 months for me. I like to dehydrate some for garlic powder and will freeze in oil so I can make it to the next harvest.

I do occasionally buy new garlic to get additional varieties - Peaceful Valley in California is good and will have sales around mid-November, as is Maine Potato Lady which is cheaper and better quality but sells out fast. I have a lot of favorites but probably Georgian Fire is at the top of the list. Spanish Roja for salsa... Purple Glazer for roasting, Music for every day use.

You can certainly plant garlic you buy from a store and it's way cheaper but it will almost always be softneck and usually "California Late White", which I find very meh. You also run some risk of picking up something like white rot (Sclerotium Cepivorum) which can persist in your soil. But the good news is that even though seed garlic is expensive it can be a one-time purchase since you just replant every year.