how to set up a pulley system for hanging plants?

Answer 1

Your question is rather brief, so below is a link to information on mechanical pulleys.

You can put pulleys on the flower pot or on the ceiling or both. You can gain a huge mechanical advantage using some of the multiple pulley designs (see figures on the web page)

Keep in mind that the installation is only as strong as the anchoring points. You need a really good attachment to the ceiling.