First of all, why do you set the beats per mesure at 2? there are 4 beats per mesure in that song because it is in 4/4 time, not in 2/4 time. She strums the chords 2 times but she also plays the bass note 2 times per mesure and that counts also as a beat.

Second ; it is always a good idea to listen to the songs and count the beats per minute so you will notice that even the instructors in GT don't always play at the speed the tabs are saying, this song for instance is not at 140 beats but somewhere around 132 beats so making it a lot easier to play along with.

Hope this clarifies stuff, Herman

Been looking quickly through Lisa's lessons and don't find anything explaining time signatures so I will do it here.

The time signature is at the beginning of the staff ( for solfege ) or tab and is a combination of 2 numbers with a slash in between them.The number behind the slash tells you the note value which is used for the count 4 is for quarter notes, 2 is for half notes and 8 is for eight notes etc. The number before the slash tells you how many of those notes are in one beat like 2/4 means that there are 2 quarter notes in one mesure, 4/4 means that there are 4 quarter notes in one mesure, 9/8 means that there are 9 eight notes in one mesure.

As for the tempo, it is usually set to beats per quarter note but is not always the case that's why you always look to the tempo and see which note is specified with the beat.

Hope this helps even more 'cause it looked to me that you didn't know about this.