Calc xls app

Hello,

Just bought and downloaded Mariner's app Calc XLS to my iPad

Have xls files that were emailed as a zip file. They open when I select, but cannot find any "open in" option. They simple open.

When I open my Calc XLS app, I have a few option at bottom of page, but nothing close to "open file."

I'll be 73 next month, don't Drop Box, don't iCloud, etc. I simply wish to open a file with this app.

So, can any one tell me how to easily open an xls file in Calc XLS?

Thanks,

Patrick