Well I've been trying to make sense of the form. (For anyone else who cares to take a look, it's here: www.hmrc.gov.uk/forms/sa800.pdf ).
The trick with most tax forms is simply to work out what you can safely leave blank (which, in your case, seems to almost everything!).
Since your annual turnover was less than £77,000 (and, at the current time, can reasonably be assumed to be so if you'd traded for a full year) you can completely ignore page 4 and simply fill in boxes 3.24 to 3.26. (Put your loss in brackets for 3.26 and copy that figure, without the brackets, to 3.84)
Since you're not going to pay any tax anyway, you can safely leave the rest of page 3 blank.
Enter '0' for 3.83 and, if you've not got a balance sheet, leave the rest of page 5 blank.
If there's anything else you need help with, please post again.
Anyway, there's no great rush. The 31st October deadline only applies to paper returns. You've got until 31st January to sort out your online one.