Remove the grommets (little metal circles) from all edges of the tarp. (You can use a large sheet of canvas with a rubber underside instead of a tarp.) Fold over 3 edges about 1/2 inch. Pin it down. Use your sewing machine to sew 3 channels. These will be used for the steel rods. Sew the thick rope to each of the two corners that'll be away from the house. If you're good at hand sewing, you can do that too.
Tie each rope end with a slipknot. Attach the wood to your home above the deck at the height position you'd like the awning to be. Place 2 large hooks (bike hooks sometimes work) at each wood end. Make sure the wood is varnished.
Screw 2 2-by-6s to the rails on the far side of your deck. You can double up the pieces if you'd like to make stronger poles. Before you do this, make notches in the same location at the top of each piece of wood. The wood should also be varnished or stained.
Slide the 3 metal rods into the 3 channels you created. If you need to cut them down a little, use a hacksaw and metal file. Sew the ends closed. Get someone to hold the tarp while you hammer it to the piece of wood. Pull the rope--this is a 2- or 3-person job--and attach to the wood you've hammered to your deck by tying the rope in the notches.
Roll back the deck awning and use the rope to tie it to the 2 large hooks when you're finished using it or during windy conditions.