This year was also our first time with our own sheep, prior experience being three evenings at the local agricultural college lambing courses and a 24h session on a farm. All in all probably delivered about 20 lambs between the two of us with a mixture of normal and malpresentations. However, the courses were very interventional - most got pulled, which is good for learning what you are feeling and getting some confidence with correcting issues and doing the manual stuff, but not so good for learning about how long to wait and how an unassisted birth will proceed - or, as we realised doing our own, what happens next and how that should happen, how long it should take etc.
For what our very limited experience is worth we brought them in only about 10 days before the due date (but they are Hebrideans so don't like being in so much). Had all the equipment etc on site well before that, but it was boxed up in labelled, task-specific tubs (maybe overkill!) by the door 3 days before the due date (they were sponged).
We started checks on the Friday (due Monday) and as it happened there was a lamb out late on the Friday night. So we began checking every 2 hours from there - but looking at other threads on this question this is very frequent compared to others, so probably overkill. It also isn't going to be sustainable for one person. The one ewe that needed assistance lambed in the early afternoon, the rest mostly sorted themselves but I did release a couple from what seemed like quite rubbery bags - would the ewe have sorted it quickly enough if I wasn't there? Don't know.
Have a look through the other recent thread on this and I'm sure there are some other older ones too. Good luck!