Here are some tools to help you through the Measurements in Science homework assignment.
The video linked here methodically takes you through the dimensional analysis process, and it includes a quiz so that you can check your understanding.
This page has a lot of practice problems worked out for you, and it explains the process in easy-to-understand language.
Here’s the presentation we’ll use in class. Watch it. Study it. Master it.
Oh, and here’s another link that may be helpful. From Texas A+M University.