Scripting a new summoning spell

On to the third part-- setting up a test cell.
"Now, hold it just a second there, why do I need a test cell?", you might ask.
To avoid this wonderful little message later on, of course.

Setting up a test cell

Click on the World menu.
Select Interior Cell.

Click the New button in the Interior Cell window.

Type a name for your new cell in the New Interior Cell window.
I used "Alit Summon Test Cell", though there's absolutely no reason why you couldn't use "Joe's Fry Shop" or "DJ Ninja Monkey's Retro Dance Emporium". We're not going to use it for anything but a place to hold one of our edited alits.
Click OK

Take a look at the Cell View window in the lower right hand corner of the CS.
Find your new interior cell in the Cell Name column.
Double click your new cell's name to open it in the Render window.

Click the Creatures tab in the Objects window.
Left click on your new summoned creature.
Hold down the mouse button, and drag it into the Render window.
It doesn't matter where in the cell your new creature ends up.