Sure, here are some steps to change the fuse on LED Christmas lights:
1. First, make sure that the power to the lights is turned off.
2. Then, locate the fuse and remove it from the light set.
3. Replace the fuse with one of the same amperage.
4. Reconnect the power to the light set and test the lights to make sure they're working properly.
5. If the lights still don't work, check the fuse again and make sure it's properly installed.
I hope that helps!