Hey we've all been novice at some point!
I'd try picking up some carbonation drops. These are easy to use and aren't too expensive. Will help you dial it in. If not, start small and build up. Put 1/8 teaspoon in a couple bottles, 1/4 in some others, leave them on the counter for a few days then start putting them in the fridge, one per day to space it out. Test to see if you like it, and when it's at it's peak. Use thick, pressure safe bottles. Have fun with the science of testing!
Alcohol will not kill your yeast, there will be plenty to eat the new sugars.
Cheers
The easiest way is something like these drops
Or you can rack into another container with enough sugar for the whole batch (usually about .9oz dextrose per gallon), and bottle fill from there.
Carbonation should be finished in 3 weeks at normal room temperature, but longer won't hurt anything.
Even once you get down to 1.000 there will still be active yeast in your cider. You just need to add a dose of some sort of fermentable sugar to each bottle and you'll have carbonation in a couple weeks. I use these tabs to bottle carbonate and I'm getting nicely consistent results.
My drinking buddy brewing friend uses something like this for bottle conditioning: https://www.amazon.com/Coopers-Home-Brewing-Carbonation-Drops/dp/B003E5ZYB8/ref=pd_lpo_328_t_1/132-8581428-0196540?_encoding=UTF8&pd_rd_i=B003E5ZYB8&pd_rd_r=24a9f00d-1ade-447b-a0ed-423342e2ca95&pd_rd_w=0GUZO&pd_rd_wg=O5PDp&pf_rd_p=7b36d496-f366-4631-94d3-61b87b52511b&pf_rd_r=6Q2P9Y8HA54VC9C8JFES&psc=1&refRID=6Q2P9Y8HA54VC9C8JFES
Depending on size of bottle, drop 1-2 in the bottle, fill bottle, cap and done.
I use these for my cider and haven't run into problems in the two years I've done it.
https://www.amazon.com/Coopers-Home-Brewing-Carbonation-Drops/dp/B003E5ZYB8
Can pick up some of these , drop one in and recap. They are normally a waste of money, but I think they are the best solution to save beer that has already been bottled.