Manual instalation: copy gui folder in your actual res_mods/version. Make sure you uncheck vehicle tier option from game.
If you don't use a XVM config, icons will appear mirrored. If you use a XVM config and icons doesn't appear correctly (it depends on xvm author's personal config), you can fix it editing the file sirmax.xc and/or battle.xc located in …\World_of_Tanks\res_mods\xvm\configs. You only have to change “mirroredVehicleIcons”: true, for “mirroredVehicleIcons”: false,