What is the best way to study for an Algebra test?

It boils down to your personal study method .

Some people will find doing many challenging excercises in their mathbook a good way of practicing for your test, as if you can do hard problems you can also solve the easier ones.

Some people will find it helpful if someone explain the concepts involved to them visually or orally, for example in an online video or a lecture.

Some will find it helpful to try to visualize algebra physically , e.g in terms of currency or objects (An apple costs 5 times for than a banana and an orange together...)

Personally, my way of studying algebra is to do many excercises and to dare challenging yourself. Eventually you become acquainted with the methods involved and it almost becomes like "muscle memory".

Doing maths is therefore similar to doing sports, in order to maintain your shape you must practice often, and challenging yourself often makes the greatest progress.

Hopefully this gave some inspiration.

For any test, there are always 2 ways to study:

Learning the content for the test (what is in the test)
Doing exam questions or practise questions.

If you do not remember anything about the test you're studying for, the best thing to do is to go over the information you need to know for that test. This can be done by:

Watching videos
Creating mind maps
Doing flashcards
or any other alternative method.

If you want to practise questions you can get this from:
Online
Workbooks
Teachers
Youtube

But overall, it is really down to personal preference to which way you study for a test...

But good luck :)