This feature is for the price table (when you use the responsive booking page the modules "Price Table" and "Price Calendar"). To activate the column go to SETTINGS -> BOOKING PAGE -> PAGE DESIGN and set ''Show Extra Maketing Column'' to ''Yes''.
When you go to SETTINGS -> BOOKING PAGE PROPERTIES -> ROOM CONTENT ROOMS->SET UP and you will see a new setting MARKETING COLUMN. Here you can set the headline for your column and the content for the price row. Then go to SETTINGS -> BOOKING PAGE -> ROOMS PROPERTIES ->OFFER 1 OFFERS (OFFER 2, OFFER 3, OFFER 4) and enter the content for each offer.