For a number of years now many teachers have complained that too much is expected of them and that they should have more help in the classroom and also time to prepare, plan and mark work. Most teachers have a TA working with them but often they do not have a TA with them all day. IF the teacher needs to go out the room, they cannot leave the children unattended so this makes it very hard for them if they have no TA.
A teaching assistant can sit with a small group of children or sometimes one or two individuals to help them with the task that has been set. It is their job to ensure that the child understands what they need to do and to possible help them explore the answers.
IF you are struggling to control a disruptive class then you may decide to split the class up and ask the TA to take a group so you can concentrate more of your attention on the ones that may need it.
At present, although they want to limit the number of teachers that have contact with the students, they also need to ensure that they have adequate cover should a teacher go off ill or isolating.