Unable to apply for SB 1 visa appointment

I am a green card holder in US, but have stayed in India for more than a year due to a complicated pregnancy. Now I need to have a SB1 visa in order to go back to US. For that I need a consular appointment first to confirm my eligibility for the SB1 visa. I have created a log in in the new website but when I try to complete an application for the appointment, it keeps asking for a DS- 260 confirmation number, which I do not have because it comes at a later stage of the SB1 visa process. I am stuck. Can anyone help?
Thanks
Padmini