Storm King's Thunder: Activating tokens?

So, I'm fresh to Roll20, at least using it, and I was purchased the Storm King's Thunder campaign for myself and my players. I was curious, How do you 'activate' certain tokens, as they are grayed out for the purpose of waiting for a specific 'event' or 'action' to happen and activate them (SPOILER AHEAD!!!!) such as the black pudding being touched in the Dripping Caves. Please advise friends, time is of the essence! :D

The translucent tokens are on the GM layer. You can switch to that layer using the tool palette at top left or with keyboard shortcuts. When on that layer, select the token (or tokens) and use the right click menu or keyboard shortcut to move them to the objects layer. 

I figured it out right as I made this post LOL! Thank you for quick response :D