Did you use PROGRAMS or EMAILS within the engagement program? If you used programs, did you ensure the smart campaign that sends out the email, included a "Member of Engagement Program" filter in the smart list?
The "leaf" icon is a "plant" icon (for nurturing/growing) to represent the overall engagement program. Within the EP, you can use individual email or full Marketo programs (we use the latter, except in my example below). You're using simple emails. Have the members of your EP received these emails before? Click the "leads" view to see who, if any, received the last cast (and all casts).