A plumber installed 2 new faucets at double sinks and a scauld-guard shower faucet in the shower, what do I need to do because I can't get hot water to work in the sinks unless I run either hot water or cold depending on which sink I am using and I have to run cold water in the sink to get hot water in the shower, please help?

A plumber installed 2 new faucets at double sinks and a scauld-guard shower faucet in the shower, what do I need to do because I can't get hot water to work in the sinks unless I run either hot water or cold depending on which sink I am using and I have to run cold water in the sink to get hot water in the shower, please help?
Did he install tempering valves on either one of or both of the sinks?

This sounds like a cross connection problem.