lots of variations to your guestions,,
I will try,,
sinew will pull reflex into a bow
some do heat in reflex and then apply sinew
some string backwards and apply sinew
it all depends on desired results
some tiller to half draw and then apply sinew
some just floor tiller and apply sinew
there are so many variations of how to proceed,, I have tried many variations with postive results, I think sinew is pretty forgiving in its application,,
just start out simple,,and then experiment as you gain more experience,,