Complex sentence: Week of Welcome is the first week before school starts in the fall for incoming freshmen; each WOW group has a different number and the leaders of each group take their students to Bubblegum Alley to leave their first mark on the city.
Split into simpler sentences: Week of Welcome is the first week before school starts in the fall for incoming freshmen. Each WOW group has a different number and the leaders of each group take their students to Bubblegum Alley to leave their first mark on the city.