My top tip would be not to bother with a whole week for activities to get to know the class; you will get to know them just as well, if not better, if you go straight into actual lessons. Have maybe a morning or half-a-morning to establish rules, routines, class charter etc. Then start teaching as normal. The children will like the structure, they will see what expectations you have in terms of work and they will pick up the class routines much easier if they are actually doing them. Go in a bit harder than they would expect, as it's easy to back-off later. If you spend a week doing nicey-nicey stuff, it will be much more difficult to get them settled into lessons.