Looking to update Packages and ThinOS but.....

Looking to update Packages and ThinOS but what is listed on the downloads page is confusing. 

We use dell 5070 and i wanted to see what the update process looks like for updating Thin-OS and the horizon agent. however the names of the downloads are very cryptic. 

1. There is the ThinOS 8.6_111 Horizon package for Dell Wyse thin clients with ThinOS and Dell Wyse thin clients with PCoIP however that is just a small pkg, so not an OS. Does that just update the horizon agent? 
2. Then there is ThinOS 8.6_111 English Merlin Image file for Dell Wyse 5070 Extended Thin Clients & ThinOS 8.6_111 English Merlin Image file for Dell Wyse 5070 Extended Thin Clients.Those look more like operating systems but i'm not sure which one i need, or the difference between the two. 
3. I have read the below guide but a little confused if that relates to BIOS or ThinOS its self since it calls it firmware. Is that how you update ThinOS on all the clients? I read somewhere that you cant do the whole OS  trough the WMS you can only do packages, to update the whole ThinOS you have to use an USB is that true? https://www.dell.com/support/manuals/us/en/04/wyse-z90d7/thinos_8.6_ag/firmware-upgrade-using-wyse-management-suite?guid=guid-e101b9e4-f2b3-41f4-b07b-34e828017fbe&lang=en-us