Saw Smithing means hitting saws with hammers to straighten and tension them to make them stiffer. At Sawfest 2018 we were visited by Tony Walker, retired owner of Atkinson Walker, sawmakers in Sheffield. You’ll get the principles of it in from Tony in above video in 2 mins 34 secs.
Sight along your saw to see if it is bent to one side. Hit the hump to flatten the saw. Whether your hammer-face is across the saw or along the saw can be hard to work out. I suggest you start with practice scrap steel and experiment.
Here I am at Tony Walkers smithing shop learning from Bully the saw smith. He tells me to sight along the top of the saw to spot the kinks.