You can just use the bin file for 1.0.2. I would suggest using a new micro sd card for the firmware in case you want to put the stock one back in (should anything go wrong.) BalenaEtcher is an easy to use software, you basically select the image file, then the drive for the sd card, and it'll do the rest. Aftwards you put the card into the system and it should expand the drive's space. Also note that the rogue firmware does not come with emulators other than psx and snes. You can find the opks and copy them back in yourself, I would suggest looking up how to do that if you aren't sure.
Thanks, I've decided to order a 32GB microSD online to use for the Rogue firmware, and keep the original card with stock firmware on it.
I've used Balena Etcher before to prepare USB sticks for Batocera.linux, it's good software, and I'm familiar with acquiring and installing OPKs as I've done on the GCW Zero.
The installation process sounds straight forward then, but then what is the "Kernel update for 1.0.0" for? Is this needed at all?