NEVER MIND, ALREADY FOUND MY ANSWER. These projects are created as Wordpress projects with content export.
I noticed that in serveral projects, that one can download from the website of templatetoaster (the free wordpress themes), these themes consist out of serveral columns under the CONTENT tab and that you can alter these colums. But when I try to do this on a blanc project I do not see these options.
To make it more clear what I mean here are some pictures (they are in Dutch since I am from Holland). These are the options I have onder the CONTENT (INHOUD) tab:
And these are the option I see in a project from the templatetoaster website:
The word 'kolommen' means columns in english, 'achtergrond' is background, 'breedte' is width, 'rand' means border, 'marge' = margin and 'opvulling' = padding.
Can someone explain to me how I can get these options under the content tab.