To make it readable, set up a layout where the interactive container field fills the screen.
To Open the PDF in your system's default application for opening PDF files, you can either use Export Field contents with the option for automatically opening the file selected or you can:
1) use a container field that does not have external storage specified
2) use insert file to insert the file and select the "store a reference" option when inserting it
3) on a layout where the field is NOT optimized for interactive content, double click the container field
Perfect thanks Phil, went for the option as described in 1, 2 & 3.
Is there a way I can have a small preview on one page that if I click on opens another layout with the container field filling the page?
Enter layout mode
Select the small format container field
Select Button Setup from the format menu
You can set up a go to layout button option to change layouts or you can perform a script to change layouts. A script could also open a new floating window with the container field on a layout inside that floating window.
Thanks Phil, set up an button to go to the new layout.