Allowing customers to select a package when making an enquiry/booking
Firstly you have to add packages/pre-orders to your Collins admin. See "Adding/editing packages and pre-orders"
Bookings Rules Section
Scroll down to Packages section
Assign the packages you want to, to the booking type. Or tick. all packages, if you are happy for customers to be able to select all the packages you have set up in your Collins admin