no reservation required
but only early morning accept application
2 " passport photo, fill a application form, your passport (and supporting docs, most time nothing, may be one or two depend on your case)
window1 -->turn in application +fee and receiving clerk check your application and ask questions about the application, and tell you to wait for interview
window2--> visa interview (may vaived)
window3--> get your passport back with the visa sticker
most get visa the same day after a short interview
but depend on the lacation(City) and your case, some may take 2 to 5 work days. so, apply early before your trip