Back again w/another noob ? about reactor placement

[Nephthys]

I've seen a couple illustrations where reactors are placed sideways/upside down on terrain. How in the world do ya'll make this happen? (hopefully I'm still in the CW2 discussion) I can do it with Beacons & Ore Rigs, but I cannot make a reactor turn to latch on from the side. Does it have to be a singular piece of terrain? Is that the trick?

THE FOLLOWING MAY BE IGNORED:
(While I'm here, I'd like to add that like many others, I'm having a very hard time w/level 19. I've played all the way through CW1 & CW2 through level 18. Also have played Academy & Evermore on Kongregate. I'll follow some of the tips I've found so far. Well, both of them.  ;D  What I really want to say is that I am in a deep love/hate relationship with all things Creeper right now. If I met Virgil right now I wouldn't know whether to hug him or smack him. [assuming "him"]Thx for letting me vent. Any mod may feel free to delete this rant).

[TLMike]

Note that down in your control ribbon, there's a green circle which indicates the direction of gravity and the flow of creeper. Next to that, there's a yellow/orange-ish square which denotes build directions. If there is an arrow which points upward, you may build Reactors and Tech arrays on top of terrain squares. Similarly, if there's arrows pointing downward, or to either side, you my built on the surface of the block to which the arrows are pointing.

It helps to check gravity directions and build surfaces for each mission.

[Nephthys]

TYVM. I saw those icons, but I thought they related to the state of the creeper. Or something along those lines. I kept wondering when I would NEED to use them. Turns out I needed them all along.

I read all of the tutorial that is in the game. If that info was there, I missed it or else it just didn't click in my brain as important at the time. I realize that this is quite the complicated game & only the basic info could be covered.

Some things I have managed to figure out, but that wasn't one of them. Thanks again for letting me know. Appreciate ya!

EDIT: Am I the only one that thinks such an advanced society wouldn't need a couple hundred reactors to kill some creeper? ;-p