OK, clause 2. This is a short one:
Delivery of Manuscripts
2. The Author shall deliver to the Publishers a complete copy of the typescript together with the Work on disk, by the following date:
[usually a date in the past]
a complete copy of the typescript = a copy of the work printed on pieces of paper and put into an envelope
the Work on disk = a copy of the work on some kind of disc, which your computer almost certainly can't write to and theirs can't read
They don't mean this clause at all. No, really, they don't. I have only delivered one paper copy of a manuscript in the last ten years and even then I said 'Really? Do you really want a paper copy? Why?' Perhaps they didn't have a printer.
Anyway, this clause actually means 'send the work as an email attachment. It must be a Word document. We probably won't be able to open it if you use the latest version of Word because we have antiquated systems.'
Often, you get the contract after you have sent the MS. If this is not the case, check that you actually can deliver the MS by the date specified. If it is in the past, and you haven't delivered it, that's worth arguing about. If it is too soon - you won't have finished the book - argue about that. It's better to set an achievable delivery date, even if it means they get a little bit cross as this stage, than to agree to a date you can't meet and then (a) get very, very stressed and (b) make them very cross when you don't deliver on time. Really. Believe me. It is in unprofessional to let them plan their production schedule around a date you know you can't meet. If they won't budge on an unrealistic date, tear up the contract and look for another publisher. I mean it.