Usually the brakes don’t need adjustment – if you notice they pull less you may want to calibrate using the adjuster spring

You can adjust the brakes. Behind the wheel you should see a little slot that allows you to insert a flat head. Make sure to match each side. 

If they’re grabbing prematurely, loosen them slightly. 

Adjuster Spring

https://www.youtube.com/watch?v=9Tf1Bc526zE