In Tasker go to the tab "Profile":
1. Touch onto the "+" in the bottom right corner of the "Profile" tab to create a new profile with it's first (and in this case it's only) condition
2. Touch"Event" - "PlugIn" - "AquaMail" for create a new condition
3. Touch the pencil next to "Configuration"
4. A new window appears with the possible settings for AquaMail - here you can select a wished mail-account or leve it empty for all
5. Touch the "<" (Back)-Button in the upper left or your system-back-button to leave the "Tasker - AquaMail > Tasker" window
6. You'll see all variables what are availiable in the "Edit Event" window
7. Touch the "<" (Back)-Button in the upper left or your system-back-button to leave the "Edit Event" window
8. A Popup-Menu appears in the "Profile" tab for creating a Task what will be done, if the condition matches some time
9. In this popup menu you have to select "New Task" and write a unique name as label for it (for example: "Speaking AquaMail") - but this label is optional, you also may let this field empty and just press the hook in the right of this lable
10. The screen changes to the "Edit Task"-page. Here touch onto the "+" in the bottom middle to add a new task
11. Touch "Alarm" - "Speak"
12. In The Textfield touch the icon in the right and choose wished Variables. to add more, you have to let a space char between them (You can insert own Text, if you want to For example "New Message from %aqmfrom with the subject %aqmsubject and the content %aqmtext")
13. Touch the "<" (Back)-Button in the upper left or your system-back-button to leave the "Speak" window
14. Touch the "<" (Back)-Button in the upper left or your system-back-button to leave the "Edit Task" window
Thats it.
Special thanks to Kostya for his Declaration
EDIT: Numbers fixed