Step 1: Tap on the button in the top left (circled in red below)
Step 2: Tap on the name(s) at the top of the page and then select/deselect which child you'd like to appear in your timeline
Step 3: Tap anywhere else on the timeline to make the filter go away.
Still have a question or suggestion? Just drop us a line at firstname.lastname@example.org, and we'll get right back to you!