light bulbs and mixing potion

where r the light bulbs?
and where r u supposed to mix the potion?

The light bulbs are in the train station.

You mix the potion in the cauldron of the guy who gave you the snake venom.

when you enter the station nothing happens only the guy saying he will help with any problems what do I do help

I don't think you can do anything with the bulbs until the artist asks for them. After he does, when you reach for the bulbs the guy in the train station will ask for water in exchange.