For Robo-Advisors, do I just sit around and wait for my money to grow or do I have the option of actually selling my shares?

Yeah pretty much. You are passing money to the financial advisor and letting them make the decisions of where to invest in your money according to your risk profile.

You can choose to withdraw money from the platform anytime but not choose which specific underlying holding to sell or buy, that's their decision to make.

So it would be best you try not to look at your account too often. And trust the investment methodology the financial advisor has which got you to trust them with your money in the first place.