Board Game Arena

I have an energy die, I'm trying to use it as my main action, but it's not allowing me to use it. The next step on the track is a bonus so it is going to be a bummer to miss.

it might be that you are in the supportive action phase.
otherwise, it's greyed out so you used it already, or you don't have the right cube type.

I'm having the same issue with ironworks.
Please explain the mechanics the card including the resource cubes it requires as it appears to only need 1 energy?

Iron works has a RED arrow, therefore it is a main action.
To activate it, besides having an energy cube, you need to:
- At the start of your turn select Action
- Then do one support action as usual. You cannot select Iron Works here since it is not a support action. So just roll a die, convert one or draw two cards or other support action (yellow arrow) from a blue card.
- Then you get to do your main action, this is the moment you can click Iron Works.

I think the penny has just dropped:

You have to build the card first (it's a blue card), and then you can use it it a later turn for a main action. All blue cards can be used once per phase, so produce to use again.