How to share a partition or folder on a wireless network?

So, I have a laptop with Windows 10 Pro, a desktop with Windows 8.1 and an old machine with Windows 7 Ultimate. They are all coected to a wireless network. I know how to share a particular folder or directory in a LAN, but am clueless how to do it in a wireless network so that any of the above machines can access a partition or a folder on a particular machine.

I read something about creating a Workgroup but I couldn't quite figure it out.

All I want is to make a partition on any of the systems 'common' so that it could be used as a common data dump site. Any machine having the password of the wireless coection should be able to access that partition.

Any pointers in that direction? Thanks!