Problem with the tutorial: When you're first directed to click the construction button it remains unclickable, as does every button on screen except for the menu button on the upper left part of the screen.
Just FYI on my specific problem: I realised a second time that after the siphon it's the harvesters that are next able to plop down. It's when you escape out of placing the harvesters before placing them, however, you get that situation where nothing is clickable.