The cladding (siding) and fascia

Step five: Blocking and purlins
From 1 1/2" x 2 1/2" lumber, measure, cut and fix two rows of blocking [p] between the lean-to rafters [l], one row across the top and one row across the middle as shown in diagram below.

Also using 1 1/2" x 2 1/2" lumber, fix two rows of purlins [q] on top of the front common rafters [k]. Position as shown in diagram below, with one row at the apex and one row just above the lean-to rafters [l].