For my two 1000-gallon rain barrels I use a shallow well pump that sends the water via garden hose to my orchard. In the orchard I split the water into four hoses so I can water four trees at once.

A search on the internet finds several pumps designed for rain barrels. There are many to choose from at a wide range of prices.

You could consider using gravity by raising the tanks onto blocks. I water my berry patch with a large tank and a garden hose. In the berry patch I have five-foot sections of howe with a “y” between to control the water flow at the open end of the “y”.

I hope the pictures come through for you.