Pages Problems after Update to Version 10

I have just updated Pages to version 10 on my iMac. Have restarted the computer. When I select and open a pages document, more than one opens. When I close one of them, they all close. Struggling to find a setting in preferences to alleviate this. Any advice please? Thank you.

And a word to Apple: I resent the fact that with every update we do, new glitches arise making the functionality of the iMac problematic. Also the search feature slows down with the updates.