Triggers are "Wings", "Sing" for sounds
Link to Doves w Trig to Start Flying http://www.imvu.com/shop/product.php?products_id=22412601
Derivable, Please dont set your version to derivable
To change image make a .png texture w any thing you dont want seen transparent and name them Dove.png and Dove1.png.
Dev from product then on top middle open asset folder and paste your textures in it w correct names, Dove.png, Dove1.png
To change or deleat sound triggs go into actions tab and change .ogg file or trig words.
To Make a trig to start them flying, in Debug2 tab under ParticleSystems where it says InitiallyEnabled / true, change to false and Trig in Actions will be "Doves"
If you would like help w Deving my particle systems just in box me, TY