1) Read directions
2) Do not update to any 5.9.x version firmware until the introduction section of the jail break no longer says in red print: "version 5.9.x not supported".
Since that is all water under the bridge in your case ...
Try to install the attachment to:
https://www.mobileread.com/forums/sh...68&postcount=4
You can put it in the topmost visible level of USB storage and then:
Install with UYK menu entry
or
Install by rebooting the device.
It is a specially built package, built so that it does not need MrPI to install it.