Flip the bike over so you can move the rear wheel (and thus the chain) freely.

Apply lube to the chain while using a rag to catch any excess lube. Be sure to turn the pedal cranks to move the chain as you pour the lube. This will make sure that the chain is fully lubricated.

Wipe off any excess lube with the rag.

Excess lube remaining on the chain can collect dust and dirt, leading to future rust and potentially undoing all of your progress.