Git on server

I work in a studio and we have many projects that we work on. We want to start using git, but we seem to be having some problems. I need to be able to pull the files from the server on to the local machines or have user repositories where the employees can pull the files to their repositories work on them then push the back to the main repository. I have tried to create a main repository and user repositories to try and push and pull between them and had no luck, git is installed on a Linux server and we have Mac and Windows machines. Any help is greatly appreciated and if more info is needed please let me know. Thanks in advance!