I am assuming by collection, you are meaning generics like List<>
Double click the class to open properties.
Click on operations to see the methods
Select the return type which closely matches what you want. EG, I've selected string as I want my parameter to be List. Now click properties.
You can set prefix and suffix which will put the words either side of the predefined type.
EG, in prefix I would type List< and in suffix I would type >