After placing the bonding on the tooth (glue), do u have to use the led curing light?

When
composite bonding material is placed in a tooth, it is soft so it can be easily
sculpted to the desired shape. Light cure composite is hardened, or cured,
using a light source which could be halogen, LED, or even laser. If a curing
light isn’t used, the composite stays soft.

Yes. You are correct, the LED light is used to cure/set up  the bonding material.Hope this helps answer your question.All the best.