I found a nice page about it here, which is to be part of a series. There is a great applet(?), anyhow a tool for visualization is on that page, that can walk you through the steps of the search. I found it very helpful for understanding what's going on. I hope my explanation is also useful.
With the output from the Python script from yesterday, we'll try using BWT to search for the query
GGATCin the text:
We'll work from the end of the query backwords. The rows we're working on can be found in the output from the script, which is listed at the end of this post.
Q1 = C.
Begin by selecting all the rows that start with C: