You can't because it's a cumulative update with 8.1 GRD1 other updates and WP10TP update but HTC 8X can't recieve WP10TP for the moment.
I have the GRD1 on my 8X but with the Insiders Bug my phone go to WP10TP i restore on stock rom but now i have the same error 80188301 and i lost the GRD1 cortana etc...
Wait and See Feb 2016 for the release client of WP10 on our 8X.
I hope you understand my post because English is not my language