@RockingLR33 

I'm also guessing that you are talking about "pick up" beats.  Pick up beats are notes played prior to the first measure.   Assume a score with 12 measures, in 3/4 time with a quarter note preceeding the first measure.  We count in the imaginary first two beats: "1, 2"  and the music begins on the 3rd beat (the quarter note preceding the first measure). Then we continue to play each measure with it's 3 beats, until we get to the last measure.  In the last measure there will be only two beats.  The result is that the music comes out with the correct total number of beats for 3/4 time: 12 * 3 = 36 beats. But one of those beats is at the very beginning and two are in the last measure.

With up and down beats, imagine tapping your foot. When the foot is in the uppermost position, that is the up beat.  When the toe is on the floor that's the down beat.  Most music puts emphasis on the down beats, but some music such as Reggae, puts the emphasis on the up beat.  When the emphasis is on the upbeat it is referred to as a "back beat."

Hope this helps.  If I'm wrong in anything I've said, please feel free to correct me.

In some styles of music, the pick up notes are primarily present for one or two reasons, they are there to let dancers know when to take their first step (right after the pick up notes), or to let other band/orchestra/group, members know when to begin playing their parts.  There may be other reasons, that others can point to.

Think of pick up notes as simply a rhythmic introduction.  Also, pickup notes are unstressed.