Yes, installing to the Content folder is fine (though I prefer to install outside the program Files folder, and in general it's a good diea not to put data - such as content files - in there). You just use one of the folders in the list, or create a new folder (anywhere that's convenient, but don't nest them - don't put a new content folder inside a folder you are already using as a content folder) and use the Add button to select it. In Windows you can simply double-click the zip to open it, then drag the Runtime folder from that into your chosen content directory and everything should go where it needs to go.