Inserting text at pre-determined place

I assume you're using Php (I don't know anything of the other languages )
As you know you call the class of the editor with this code:

$oFCKeditor = new FCKeditor('text');
$oFCKeditor->BasePath = '/fckeditor/';
$oFCKeditor->Create();

So you always want to insert at the beginning of the document? Is that what Line 1 means? Do you want your plugin to insert at the beginning and then return control at the previous selection point, or is it okay for the selection to be reset to the end of your plugin's output?

There are several selection functions that might help, depending on your needs... (None documented outside of the source, though...)