The top level share permissions are dictated when you create the Share via the User Control Console. These can then be managed in the User Control Console or in AD under the HAP OU:
https://support.zynstra.com/hc/en-us/articles/201839041-User-File-shares-and-Permissions
The files and folders underneath can be manage like any normal Windows computer or file server:
To set, view, change, or remove permissions on files and folders
1.Using Windows Explorer, Right-click the file or folder for which you want to set permissions, click Properties, and then click the Security tab.
2.Click Edit to open the Permissions for <Object> dialog box.
3.Do one of the following:
◦ To set permissions for a group or user that does not appear in the Group or user names box, click Add. Type the name of the group or user you want to set permissions for, and then click OK.
◦ To change or remove permissions from an existing group or user, click the name of the group or user.
4.Do one of the following:
◦ To allow or deny a permission, in the Permissions for <User or Group> box, select the Allow or Deny check box.
◦ To remove the group or user from the Group or user names box, click Remove.