Re: Creating a World - Bare Geomod
"BG Medieval" will install into the "...\Medieval II Total War\mods\Bare_Geomod" folder. If you make changes in another mod folder, then these changes will not appear there. changes in the "...\Medieval II Total War\data\loading_screens" folder should appear there.
I would however advise you to follow this tutorial from step 3 onward.
May I ask why you are using the Medieval version of Bare Geomod and not the Kingdoms one? If you have any of the Kingdoms campaigns installed, then I would recommend to use the Kingdoms version.