Expressing milk for working mums

Hi mummies, any advice for a FTM here? Going back to work in couple of months, any advice or suggestion on how should I go about expressing my milk during work hours? Do I do it on a 3-4 hourly basis or as and when necessary? How do I store it and bring them back home? Do I need a cooler bag just for my milk? Please help!!! Open to any advice and suggestions!!