When in Collins, go to Floorplan (third tab in the top bar).

If you have multiple venues, select the Venue

To the left of the screen is your Check-in panel

To allocate tables or change tables for a customer:

Click on the booking name in the left hand Bookings list

There will be a button with the Table number/name the booking is placed in or if they haven't been placed into a table yet this will display an arrow icon > click on the button > this will now display 'Done'

If they are already assigned a table this will go purple. To change the table to another one, simply click on the table they are in (the purple will disappear) and then select the table you want to put them in (you can select multiple tables, turning them purple)  

When happy with your selection, select the 'Done' button again and it will save them in the table(s). 

NOTE: All changes made in the visual Floorplan are obviously reflected in the grid view automatically too. And vice versa.