Your Babel box is for saying what languages you know, as well as what operating system, keyboard layout, web browser, desktop environment, and text editor you are most comfortable with. Details of how to use it for its original purpose, saying what languages you know, are at Wikipedia:Babel. Details of how to use it to say what technologies you use are fairly scattered, but a large assortment are at Category:Wikipedians by technology, or in Category:Wikipedians.
Template:Babel - Allows 1 to 100 boxes. Format: {{Babel|<box1>|<box2>|<box3>...}}
Template:Babel-N - Allows any number of boxes. Format: {{Babel-N |1={{User <box1>}}{{User <box2>}}{{User <box3>}}...}}
To customize the appearance you can add the optional parameters header=HEADER (default: Wikipedia:Babel), footer=FOOTER (default: Search user languages), bordercolor=BORDERCOLOR (default: #99B3FF), color=COLOR (default: white), textcolor=TEXTCOLOR (default: black), left=Left margin (default: 1), bottom=Bottom margin (default: 0.5), solid=Solid border width (default: 1), width=Box width (default: 248), and/or extra-css=<any other formatting>. Call the '!' userbox to start a new column after that point or the '-' userbox to insert a blank row. You may also use '|align=left' to display the babel box on the left side of the screen rather than the default right. Boxes with parameters can be added at the end with the format, "|special-boxes={{box page name|param1|param2}}{{second page name|param1|param2|param3}}". Any number of additional boxes can be added this way and will display below the others.