Now that you have the blind all the way up, you may need a flat head screw driver.
First try this: With your thumb or a screw driver you will want to press underneath the bracket then the cover should swing open from the bottom.
Once you have done this the bracket will open toward the top. As you can see, the bracket arm is now facing up.
If you can’t seem to get that to release, use the screw driver to help push the bracket underneath up a bit to release the cover.
You do not need to do BOTH brackets but it makes it a bit easier to get it in and out of the brackets if you do.