DWP Conditional Job Offer- Help!

Hey,

I've recently gone for a job at AO level in the DWP. Was put on the reserve list but a new offer has come up that I'd like to go for. I've hit a snag though, and as I've used these forums for support during the application process (lurking, not posting), I thought I'd sign up and ask you guys since you seem to know your stuff. I'm hoping I'm okay to ask here as I didn't see anywhere my question would be better suited to.

I have a ton of forms to fill out that I've got through the Civil Service Jobs portal. They're all downloads and I have no idea where to submit them once they're done. On one of them it says to take it to the interview but I got them way after I'd been put on the reserve list (but before my job offer, strangely). I don't have any contact details aside from the email on the original advert but my offer is for a completely different part of the DWP so I'm at a total loss as to what to do about it. Hoping I'm being daft and I've missed an upload link or something on the job portal!

Thanks in advance for any help you can give me, I just want to avoid being a nuisance to someone at the DWP because at this point all I can think of to do is just email whoever I can and try and get them to pass me on to someone who can help. It's not an ideal first impression though!