If I place scenery directly into a Tamriel worldspace cell (i.e. say a small campsite or a small shack without doors that requires no interior cell, I gather I must place some kind of markers immediately surrounding my scenery when viewing it from above in the CK render window in order to create a smaller cell within the larger 'wilderness' cell that I've placed the scenery in (i.e. whereby my own smaller cell will be created and will then be separated from the larger wilderness cell)?? I gather this must be needed so that if I upload my scenery and someone installs my .esp mod file, then my mod won't potentially interfere with any other mods that may possibly be altering any of the other space inside the larger 'wilderness' cell that I initially placed my scenery into?

To give me a proper understanding of this, I need to clarify exactly how I enclose the immediate area around my scenery item. Do I use those red Xmarkers for that?? I've only just started using the CK, and this is something in particular that I'm not entirely sure about, so this is why I ask.

Any clarification on this would be appreciated.