From the dashboard, or the drop down menu in the top right of the screen, click the Metrics icon.
Click Settings in the top menu bar
This is where you set up which statistics will be collected for each type of event/service you hold. From the list of categories, select the one that matches the event you want to set up.
Then click the Add Metric Collection Series button and you will be able to add your first category. Select the data you would like to collect from the Select A Category drop down. These are split into four groups - Attendance, Spiritual, Visitors and Other.
Once you have selected this, an empty text box will appear next to it. Type in here what you want this category to be called. This will appear in the list in Abacus where you will input the figures each week. For example, you may want to create a different category for each of your childrens groups, you can type the name of the first group in this box.
Click Add to add this series to this event category.
See the help section on Abacus to find out how to start recording your stats.