How can I change the bike stem?

To change the bike stem, follow these steps:

1. Loosen the bolts on the current stem using an Allen wrench.
2. Remove the handlebars from the stem.
3. Slide off the old stem from the fork steerer tube.
4. Slide on the new stem onto the fork steerer tube.
5. Reattach the handlebars to the new stem.
6. Tighten the bolts on the new stem securely.

Remember to adjust the stem to the desired height and angle before tightening the bolts.