1. Size
Width and projection
Width is how far the awning runs along the wall. Projection is how far it reaches out from the wall when it is open.
Start with where it can fix. It goes on the wall, under the rafters, or up at the roof line. Then work out what you want shaded, such as the table or the lounge, and measure how far that sits out from the wall. That is your projection.
Width is made to your wall, up to 9.0m on a Titan Flex and 7.5m on a Millennium. Projection comes in set steps, and the deeper steps are only made on wider awnings.