To change the current category, click the "Category" toolbar item. This will open the category drawer. Simply clicking a category name within the drawer will make that category the active one.
Registered users can create their own custom categories. There are '+' and '-' buttons in the category drawer that will be active for registered users.
You don't need to know what a Perl-type regular expression is to make basic use of this feature. The simplest expression is just a string. For example, a category defined with the expression:
confidentialwould only display transfers with "confidential" somewhere in their filename. As another example, to display only files with the MP3 extension, the expression:
.mp3could be used.
A slightly more advanced example would be to create a "Music" category that included both MP3 and M4A files. This can be accomplished with the expression:
.mp3|.m4aThe '|' character is used as an "OR" character and allows you to define one or more strings. If any of those strings are found, the expression would be true and thus the transfer would be displayed.
These are, of course, all very simple examples of what is possible with Perl-type regular expressions. There are many excellent resources on the Internet for learning about them. Click here to do a Google search for regular expression tutorials.