here is the Create folder command:
New-Item "C:\Shared" –type directory
If you are creating multiple levels at once (like "C:\NewRootFolder\NewChildFolder\NewShared" you can add the –force switch to make it create all necessary parent folders in the heirarchy)
Now that you have a folder that you want to share, you can turn it into a shared folder using the New-SMBShare cmdlet.
New-SMBShare –Name "Shared" –Path "C:\Shared" `
–FullAccess domain\admingroup `
-ChangeAccess domain\deptusers `
-ReadAccess "domain\authenticated users"
How to Create a Network Share with PowerShell 3