How can I adjust my bicycle handlebars to ensure they are in an upright position for a more comfortable riding experience?

To adjust your bicycle handlebars for a more comfortable riding experience, first loosen the bolts on the stem using an Allen key. Then, adjust the handlebars to the desired height and angle. Make sure they are upright and aligned with the front wheel. Finally, tighten the bolts securely to hold the handlebars in place. Test the position by riding the bike to ensure it feels comfortable and stable.