Each child has different needs in terms of adapting to new realities/routines.
Entrance to the nursery/garden /kindergarten is always a source of concern for parents.
A good option is to plan a few days of adaptation where you stay with him there. Evaluate, for yourself, if he is integrating and help him do it: helping to find toys, showing all the rooms, establishing trusting relationships with caregivers, introducing other children …
Another important aspect is our example: our children react instinctively like ourselves, that is, if we are anxious, they will show signs of anxiety, if we are suspicious of the people who will be their main caregivers, they will not trust those people, etc.
So I recommend that you take a deep breath, trust that it will go well, leave your watch at home on those days (go without schedules to leave or return), focus on your child and help him discover everything! He will give you all the signals you need to assess how you need to plan ahead!
As soon as you see that he is integrated, establish a goodbye routine (kiss and hug, for example) and leave. This may not happen on the first day or the second, but it must happen sometime. Mark at the calendar the deadline, the last day, for him and for you.
Never try to start thinking about leaving if you are not sure that it is the best decision and that you are going to leave (and leave him there). When you start the goodbye routine it should be a point of no return from which you should not hesitate or go back.
When you leave (alone), if your heart gets tight, it’s normal! If you want to cry, cry, throw it all away! Life is made up of stages and this is just one more. Above all, it is very important that you make sure that, deep down, you know that you are doing the best for your child! So prepare yourself and make your own adaptation to the new reality, but without interfering with his (and preferably without him realizing).