How do I use bricks to make a border around my garden?

There are two ways to do this. Both require a shallow trench. If you desire the bricks to lay flat so your lawn mower can run along them, just lay them in your trench making the top flat surface at ground level and back fill around them with dirt. The other way is to stack them at an angel with the pointed corner pointing up. Again, just backfill with dirt.

Here's a video that might help - https://www.youtube.com/watch?v=DZmR4A0-1ZU

Judith: maybe this will help

https://www.homedepot.com/c/ah/how-to-install-brick-edging/9ba683603be9fa5395fab907a9ccb74

I like turning them at an angle for this purpose. Then you get a bit of height. Dig a footing, tap into place, repeat. It's slow and back breaking but well worth it.