I live in a region that has very long dry summers. I am pretty new to bonsai trees, so I was wondering if there is anything I should do to help with water retention. Will it be enough to water it several times a day or is there something more I should do? I have a small Hinoki Cypress if that changes anything.

Best way is to find someone that is doing bonsai in your own area. Or a bonsai Club.
So where are you located?

Watering also depends on the substrate you use. And that is also diffrent around the world.
I live in a country that has more rain then sun. So substrate will hold less water, resulting in more watering in summer.
But in a place where its more hot then wet, you want a substrate that hold more water.
Substrate also depends on what you can buy localy.

So without more information about the location, and the substrate you use. It is hard to anwser.

No magic and works in most places in the world: Just water when soil is moist but not dry. Use a fine shower over the whole surface area. Water until there is a steady flow out of the drainage holes. In hot summers and small pots that could be several times a day. If you feel it is drying up to quick you can look for more water retention soil and repot next spring. Or just shade the tree a little bit more the hottest days.

The size of the substrate particles affects water retention, where smaller particles retain more water. A higher content of organics (e.g., coco fibres) also increases water retention. Also it is good practice to water, wait 10 minutes and then water again. And of course, when watering, watering so the water runs out of the drainage hole. Often the watering technique is lacking, not the substrate.

It is for you to decide whether it is frequent watering, or highly retentive substrate. I want substrate that does not need watering more than once a day in all but our hottest weeks. And fast draining as we have very wet fall and winter, normally.