Hi
Great that you watched the tutorials.
You should be able to easily switch to EigenD in the normal ways on a Mac, if it's running, I usually use cmd+tab to cycle through the applications I have running, but you should also be able to click on the EigenD icon in the toolbar to raise the application window and have the available menus at the top of your screen where they usually are. If you don't have an EigenD icon on your dock you can also just drag one there from the Applications folder, where EigenD is installed. As well as the EigenD application that you'll see in the applications folder there is also an 'Eigenlabs' folder - this is where you will find all versions of EigenD that you have installed, if you should ever want to run an older version.
The performance meter does not show by default by the way, you have to select it in the 'Window' menu first.
If you find that you cannot switch to EigenD in the normal ways then something very weird is going on, especially if its running already and you can play - we'll need to look into this next week when the dev team are back from holiday if that's the case. Please be aware that it's possible to not have any windows open at all (if for example you closed the 'load' window) so when you switch to eigenD as the focused app you might just see the top toolbar change and there might not be any window to pop up - if you are used to using expose to switch focused app this might be confusing. You can still open new windows using the menus without trouble.
I hope that helps.
John