I am a special education teacher. I need to educate the students with special educational needs.
What sort of disabilities do the children you teach have?
All kinds of disabilities. Some need special equipment or teaching procedures
what age group are they in?
Can be any schooling age. Younger children (primary school age) need more care and individually planned arrangement suited to their needs. 
So do you teach in a single school just for special needs students or do you visit various normal schools and assist there when needed?
A single school in my case.. They need special education because if they were given a typical classroom teachings they would not be able to learn.
It must be a very challenging environment but also at the same time it must be very rewarding for you to see them happy