Use an Allen wrench to unscrew the stem wedge bolt a few turns. The bolt may be hidden under a protective cap, which would need to be removed first. Most models take a 6 mm Allen wrench.
Raise the handlebar stem so the top of the handlebars is about the same height as the top of the saddle.
Center the front wheel with the direction of the stem.
Retighten the stem wedge bolt.
Loosen the binder bolt, if the brake levers are not at a 45-degree angle below the handlebars. Once loose, rotate the handlebars to achieve the 45-degree angle and retighten the binder bolt.