plz answer my few questions

[vehla]

Hello
Yesterday I applied for US B2 visa to visit my wife in Arizona. I'm in calgary, AB. I'm student here and have India passport. I filled ds160 and paid my appointment fees $160.
Now what's next...?
Do I need any sponsor letter from her...?
How can and from where she can make..?
What's the difference between appointment date and interview date...?
Any other suggestion plz share.
Thanks

[immihelp]

Start with http://www.immihelp.com/usa-visitors-visa/ and read various pages there.

If you still have questions, please post them here.