Of course if you don't behave in the way they want you to , you're going to get in trouble , but most of the time they are super kind .
And most certainly , the school is big and it has lots of buildings, so you could potentially get lost the first couple of days if not the whole week! Now , this sounds scary but if you're not sure where to go, don't hesitate to ask older people : they are there for you whenever you need them!
Don't worry too much about the homework because if they do give you some, they give you plenty of time to get it done and it's not that hard : it's not like your first day you finish a maths lesson and already they give you a super hard math aquasion (e.g. : 2x8%of the mass=?%of the$ made in £ translated into € )
So there you go, that was a few advices for you in year 6 that are nervous about going up to secondary school and my top tip in this article for you is : just have fun, try and make as many friends as possible and don't worry!
;-) love u lots