Each class usually has two adults who help in that class, there's the Class Teacher and a Teaching Assistant. Sometimes there are children who have extra learning needs and so they have additional support, this is like another teaching assistant but they specifically help certain children.
Sometimes schools have a teacher who will help to lead a year group. If the school is small and there is only one class in each year group then they don't have this, it's when you go to a bigger school that you might find a Year Group Lead. Lots of secondary schools have these, they call them Heads of Year. There Year Group Leads and Heads of Years work with all the teachers in that year group to make sure that the children are learning and progressing well.
Primary Schools are split into two sections - Key Stage One and Key Stage Two. Nearly all schools will have a Key Stage Leader for each of these. They help to make sure that the classes in their Key Stage are learning the right things, progressing well and usually help make decisions about the curriculum, trips etc. In Secondary there aren't Key Stage Leaders, instead they have a Head of Department. These people usually look after one or two related subjects.
Every school has a Head Teacher who is responsible for overseeing the whole school.
There are lots of people who work behind the scenes to make sure that our schools run well. These include people like a Business Manager, Administrator, Attendence Officer, Caretaker, Site Manager and a number of Cleaners. These people are very important to school life, everyone who works in a school plays a big part in school life and the smooth running of the school.