How to determine constructor parms or open a class file

If I want to instantiate a new class, but don't know
the parameters for the constructor, is there an easy
to find out what those parameters are?

Ctrl+P (View -> Parameter Info)

Also, if one clicks on (or highlights) a class file,
is there an easy way to open it so one can see its
contents (or see what parameters its constructor
takes)?

CtrlShiftI (View -> Quick Definition Lookup)

Thanks much!!! Sorry for the double post.