Try to connect your children with other kids from their grade/new school so they have a social network from day one. You can even get the email addresses or phone numbers of similarly aged children in your community before moving.
When school starts, contact your child’s mechanech or mechanechet (homeroom teacher) and get to know them. Make sure that they are aware of your child’s needs and your expectations.
You are allowed to be a true “NBN” = Nice But Nudniky. As olim, your children have certain rights within the school. Don’t be scared to push to make sure they get these rights.