Create a separate One Drive “Cloud Administrator” account and assign a 365 license to the account and setup the One Drive Share sync. Once that is done to edit cloud permissions:
From the file server open Http://portal.office.com and log on using the “Cloud Administrator” account
Once logged on select One Drive as shown below:
It will open your One Drive Business share:
To change permissions, select the check box to the left of the file or folder as shown below:
Right Click and select Details as shown below:
You will notice on the right side the file details scroll down to “Sharing” as shown below:
That will expand to show you the file or folder permissions from there you can add people, stop sharing to that person, or revise read/write permissions as shown below:
CAUTION: These are One Drive share permissions ONLY this will not impact your share permissions internally on the file share those permissions should be modified as well.
Note: I would recommend using folders and not have files in the root directory of your synced folder. That will make permissions administration editing easier.
The users will then see the data on their 365 accounts by going to the “Shared with me” folder as shown below: