I've made a few batches. Usually I start with apple concentrate. I buy enough to make 6 gallons, but keep one gallon out to sweeten after fermentation. I use wine yeast, and typically add sugar to up the "fun" factor. Usually I shoot for a potential alcohol reading of about 12%, since it gets cut later. Its been awhile, but I think 5lb of sugar will get a 6 gallon batch close. It's completely optional. You can add cinnamon sticks if you like. It should finish fermenting in a week or two. After initial fermentation, I add in the reserve juice to taste, as its pretty dry.
From this point, there are several options. I have a keg and c02 setup, so its easy for me. I kill the yeast off and keg it. The c02 tank carbonates it for me, and I don't lose any sweetness. If you don't have a keg setup, you are left with a decision, sweetness, bubbles, or a little of both if you drink it quickly. I don't bottle, so I'll let someone who has weight in on that, but if you want bubbles without a keg, don't kill the yeast. The yeast will eat the new sugar added when you sweetened with the reserve juice, and if the bottle is tight, the gas released will carbonate. You will be left with bubbly, dryer cider. I need to note...too much sweetness before bottling can cause bottles to explode.
If sweetness is important, kill the yeast, but know it won't be bubbly.
Before I had my CO2 setup, I made a batch of cider that I wanted bubbly and sweet. I didn't kill the yeast, and sweetened as usual. I put the cider in mason jars and kept them in the fridge. The cool slowed the fermentation, and the seals kept enough CO2 in to make it bubbly. The lids ended up denting outwards a bit, and had it not been so popular among friends, I could have been dealing with a cider bomb.
That's what I know...hope it helps.