input question: To attach LEDs to a brass wire,

output answer: Use double-sided tape to hold the LEDs in place as a guide. Afterward, take your soldering iron and carefully solder the ends to the wire using a little bit of solder.

input question: whiteboard

output answer: falls from wall

input question: How to prepare wood before repainting.

output answer:
Use a sander with 240-grit sandpaper to remove any old finish and paint.