First make sure the bag or backpack is not overfilled so you have enough material to roll down. Then align the top edges of the main compartment and squeeze them together.
Roll down the top of the bag or backpack at least 3 times as tightly as possible. Rolling the top tightly makes the seal better (please check the end of these instructions for the roll down closure limitations).
Depending on the model of your bag or backpack there are from 1 to 3 ways to secure the roll down top so it doesn’t come loose. The most watertight option is to buckle the ends of the roll down top together (works with all DryTide gear except 50L duffel). To make the seal even better make sure you bend the ends in the opposite direction towards the back, away from the side where you rolled the top down. You should always close your backpack this way if you will be using it in extreme conditions!
You can also buckle the ends to the sides of the backpack. This option is available with rainproof version of the 50L backpack, 30L daypack and 50L duffel. Closing the backpack this way is okay for regular use and using your backpack in rain. Buckling the roll down to the sides of the backpack makes the backpack look better (at least to most people).
Third option, available in 30L daypack and 50L duffel is to leave the roll down unbuckled and just secure it with a strap that goes over the top. This is the fastest way of closing, but obviously not very watertight.
A quick demonstration of how to close the backpack by buckling the ends to the sides of the backpack. Works with rainproof backpack, 30L daypack and duffel bag.