Thats alot of questions right there.
I am not an expert, but I can help you out a little.
To locate a bird you need to shock him into gobbling, that is why it is called shock gobble. In the morning I preffer an owl call, in the late morning and afternoon I use the crow call. You want to sound like a real bird, crow or owl. It is the sudden loud sound that makes the turkey gobble. You can you tube all the birds, to get the sounds, owl, crow and turkey.
http://www.youtube.com/watch?v=fppKGJD3Y6c
As far as turkey calls. The main ones you need to use are the yelp a cutt and a cluck.
Start off soft and slow. Again you want to sound like or mimic the birds mood in the area and on a given day.
I hope this helps. John