Enrique, here's a bit of info I learned recently, being new to BIAB also. Find a song you like on your PC and remember the folder it's in; select ACW button (Audio Chord Wizard) on BIAB main page, then find the song and select it. It will give you the chords in ACW; read the instructions when doing this; then send to BIAB. A dialogue box will appear with a few buttons; select the key, then select "Delete the audio track"; this will leave you with just the chords and the bars of the song. You can change keys, change tempo and apply any style to it. If you do not delete the audio you will have to print the chords and enter them manually, which I was doing till I learned the easy way. There will also be a button to select "Make a Tempo Map." This is ok if you want exactly the same tempo throughout the song as the original, and can be very useful, but you won't be able to enter another tempo, it will do exactly as the original, including changing tempo if there are any.

Good Luck,
Dennis