Congratulations on the job!
My suggestions are to get hold of and read all the policy documents for your new school, especially SEN, safeguarding / child protection, behaviour management, teaching & learning, marking & feedback and assessment policies, plus staff handbook/code of conduct. All that you do will be influenced by the school's policies and having a good chance to read them without day-to-day teaching commitments is really useful.
Also ask if there is a set planning format and whether there are any schemes of work already in place. With the new curriculum coming in fully in September there may be little and you can do as you want. Will you be working in a single year group intake or will you plan with parallel teachers?
It may also be worth having a good browse of the TES, Primary Resources, etc. for resource ideas. Build up a collection of useful websites for displays and resources (can't remember many as my brain is in holiday mode - Topmarks, Twinkl, etc. - there is a list somewhere on here or the TES).
Over the summer stock up on emergency freezer meals, make sure your childcare is reliable and has emergency backups, get a few outfits that you feel really good in ready, stock up on vitamins to keep your immune system strong, maybe even start your Christmas shopping and have a really good break! You may see little of your friends and family until the Christmas holidays!