I have a new apple watch, the band is a bit lose. my last apple watch I received two bands but with this one I received one which is on the looser side. how do I get a smaller band?

When purchasing the Apple Watch, you would have been given the option to select a band size.

If you selected the wrong size, you can return the Watch for a refund and get a new watch with an appropriately sized band, or you can simply purchase a new band that fits you better.

Link-> Returns & Refunds - Shopping Help - Apple

Link-> Buy Apple Watch Bands - Apple