Yes correct it would just be drag and drop
1. There is no order in extraction! All the files and folders are extracted at once. Which order should I use to ?upload??
You can just drag all files and drop them into the root of the template folder and overwrite when prompted.
2. What folders and files should I upload? For example the folder ?xml? with all of its content? Or only the content? So the folder ?language? and the file Vertex.xml ?
MInd you: the patch?s folder does not contain Specific.xml. So, if I upload the folder ?xml? the file Specific.xml is gone.
Correct the specific.xml is not contained in the patch as this file is specific to each template and there is no generic version. The specific.xml file won't be deleted when you drag and drop the patch files.
3. Same question for the folder ?css? in the patch. Upload that folder at once? Or separately the folders bootstrap, core, font-awsome, ionicons and multibox? Of even separately the content of that five folders? (this is the way we did it in the nineties?)
You just drag all contents of the patch and drop into the root of your template folder where the index.php file is and the templatedetails.xml file is. When prompted to overwrite choose yes.