Limited Company accounts - where do I start?

I have downloaded a DIY accounts package (essentially a set of linked Excel files), but need to know where to start. This is my first business (part time from home) and we have only traded a few days this year and so don't have hundreds of pounds to pay out for the complete accounts service or CT sumission to HMRC. To allow a 'B' plan, I'm hoping to be comfortable in completing the bulk of the work (allbeit the simpler stuff) by mid March.