To split a tip between 2 or more staff:

Start making a sale by click on the "Check Out" button in a booking or the "New Sale" button in the Sales menu.

Click on the "Add Tip" button in the right hand column:
​

Select the staff member who the tip should go to at the top of the pop up window and enter the tip value. Then click "Save".

You will now see the first tip that you added in the right hand column.

Click "Add Tip" again to add the next tip. Select the staff member who the tip should go to at the top of the pop up window and enter the tip value. Then click "Save".

You will now be able to see both the tips you have added to the sale:

You can repeat this process for as many tips as you need to add to the sale.