In how much advance, I can fill DS160 and take appointment date

I am planning to go back to India and get my visa stamped in October. Can anyone tell that in how much advance I can start filling DS160 and take appointment date. My plan is to take appointment date first and then book tickets accordingly.

As per my information you can’t appear for stamping more than 90 days in advance of start date i.e. 1st Oct…so u can appear anytime on/after 1st July…