Looking for advise on a software.

Just set them up as guest accounts as a simple way. There are some more advanced ways like setting group policies but you need to have some computer knowledge to use those. Policies on the computer and server are the normal way in the corporate way as well as using groups for the user accounts to manage things. You do need someone that is competent to set things up, many times you will do more harm than good just messing around with user rights.

You need to first set guidelines for what is OK to do, what is not OK to do as a official policy, as well as what the workers should be able to do on the computer, what sites are needed to visit, etc...

There are lots of programs that manage computers, even at the local computer level but they are harder to manage. If all the accounts are local, creating user accounts as a Guest account for them to use will lock them down from making most changes and you can use rules on the router or your proxy server to block web sites.