Welcome Dunda,
Everything that concerns Skin and content folders you have in one post - simply download and unzip files!
To the folder igo / content / skin Doupas 24.zip file copying, or Doupas 24 silver.zip.
When you start entering a setting / screen and select the default zamniast-day - Doupas 6.5. Same for the default - night.
The skin supports HD so your resolution will also be good.
Author Skin - DOUPAS wrote (thx DOUPAS !!!) - quoted .:

[rawdisplay]
force_renderer = "RENDER_MOYA"
;driver = engine
;driver = gdi
;res = 1
;screen_xy = "auto"
;screen_xy = "1024_768: 1920x1080 / 1080x1920: fullscreen"
;driver = gles_2_0_android
;vram_size = 33554432


screen_xy = "1024_768: 1920x1080 / 1080x1920: fullscreen"

insert these lines to your sys.txt and check - do not forget their arguments preceded by ; and, in the above-the mark removed.
.................................................. ....
and you who responded, stated that everything works ok.
* Unfortunately, I have only NOTE 2 so I can not check

As for the rest of the questions - install it and check yourself what has changed - unfortunately I do not know what you installed.
Regards wojpen

PS. Doupas again THX