Im sort of new to adding mods, especially in gog.
Could someone give advice how to install the first person horse riding mod?
i copied the mod file into patch0/bundlesdirectory but didnt work.
could someone help a bit please...

If you mean Nexusmods like this one, use this tutorial.

Or of course use the Nexus Mod Manager (NMM), which is good if you plan to use many mods or change them a lot.

I think i followed the tutorial but still doesnt work. the tutorial is guiding how to do it in steam and thought maybe installing mods work some other way in gog(?) or doesnt work (?). I'm not able to download the mod manager, opens empty page only...

It should be the same since he also mentions the path for the GOG version in the description.

[Edit] I did just try to install the mod myself and it worked fine.

ok. i got it working finally as well. i just had to update the game. the first person view is very good, at least, especially if you have a good specs :). i recommend people to try!

I am glad that you finally got it to work. :-)