Thanks for trying Scrivener!
First, what you can’t do: there is no way of viewing page numbers a the tops or bottoms of pages in Scrivener, I’m afraid. Every text editor and word processor lays things out differently, so if your editor is referring to page numbers in Word, there is no way for Scrivener to know these. Even if it displayed page numbers, the changes are that they wouldn’t match up exactly with the ones in Word because of layout differences. Also, when you work in Scrivener, the idea is that everything gets broken down into smaller segments, so page numbers don’t really have any meaning until the text is compiled - especially seeing as you can compile using different fonts and adding various elements to the text.
However, what you can do is enter page layout view for the manuscript you imported by opening it in the editor and clicking “Wrap” in the toolbar. This will put you in page layout view. Page numbers are shown in the footer bar. These should give you a general guide as to where you need to go - but bear in mind the above, that the page numbers are unlikely to exactly match those in Word or wherever, because of layout differences.
Another option: if you don’t need to edit the original manuscript and need to refer to exact page numbers (assuming you are working on a copy), you could open the original MS in Word, go to Print, save it out as a PDF and then import the PDF into Scrivener for reference. A PDF generated from Word and imported into Scrivener will show the pages exactly as-is, because PDF files always do. You could have that open alongside the editable version, or you could open it in a QuickReference window.
Regarding splitting the editor, you can do this in several ways, but the simplest is just to click on the split button on the right of the header bar of the editor - hold down the Option key to split vertically instead of horizontally. (Or you can split via the View > Layout menu.)
Once you’ve split the editor, you can load different documents into either.
If you haven’t already, I strongly recommend going through the interactive tutorial (Help > Interactive Tutorial), as this covers how to split the editor, use QuickReference panels and suchlike, and will get you up to speed with the program in the shortest possible time.
Hope that helps.
All the best,