At this time, there is only support for android phones. Android tablets are not yet supported with Lightroom Mobile. Lightroom Mobile does not have everything that Lightroom has, but does provide a good set of editing tools to allow you to make adjustments. The normal procedure is to download images to your main computer that runs desktop Lightroom. Then you create a collection that contains the images that you want to work on with Lightroom Mobile. Then the collection is synchronized with Lightroom Mobile and is available on supported devices. The only tablets that are supported at this time are iPads.