Limit on DS160 validity(days)

[jminu]

Hi All,
As I understand the process..
I start filling the DS160 and save as frequently as possible to my computer.
Then when the dates become avialable, I upload the form from my computer, choose the date and submit the form

1. Have i got the process right or am I missing something
2. How long is a saved DS160 valid(prior to submission). The dates I want are not open yet.
So if i fill now, I'm just concerned if the form will expire when dates become available

Thanks
M