Bread flour is non-existent here. And I've wanted to try making bagels... so I hope to give this a go over the weekend....
https://www.chefsteps.com/activities/how-to-make-any-flour-into-bread-flour
https://www.chefsteps.com/activities/how-to-make-any-flour-into-bread-flour
https://www.chefsteps.com/activities/how-to-make-any-flour-into-bread-flour
https://www.chefsteps.com/activities/how-to-make-any-flour-into-bread-flour