Need Advice: Prepping to Sleep Train and TERRIFIED

So my wife and I are going to start sleep training our 11 month old this Friday and I am terrified. Our baby has always been a difficult sleeper. We also never dropped a dream feed from when he was younger so he wakes up on the dot around 10 in addition to all his other wakeups. I have always been on night duty and recently I started co-sleeping with him on a mattress in the nursery because it was the only way he will get decent sleep, so when he wakes up around midnight every night, I go in there and sleep with him. It's been the only way that he and I have been able to get any consistent sleep, but to us this is unsustainable and I really don't want to continue cosleeping.

I am thinking of doing the Ferber method, I got the book PLS but we moved recently and the book is somewhere in a box in the garage (I don't have time to read it right now anyway as I am in grad school and working full time and being a parent). I am so scared of doing Ferber and am looking for some advice or tips. If you are someone who tried it, please....any words of encouragement will be appreciated.

I am mostly curious about a few things:

-How long do I let the baby cry before going in to let him know that I am here and he is okay? I heard of someone else (not sure what method) who would go in and sleep in the nursery near the baby so the baby knows that you are there. Has anyone else done this and did it work?

-I am afraid my baby will cry for HOURS....has anyone else had this experience? How did you handle it?

-Currently, he will only sleep if we rock him to sleep. Is this something I can still incorporate while sleep training? Or am I supposed to put him down awake and just leave him to fall asleep on his own?

Any advice, tips, words of encouragement are welcomed. I am scared shitless for Friday.