You can move or hide existing Apps from the Home Screen by doing a long-press on the button of your remote… a small pop-up will show 2 options (Hide or Move) - if you select Move you can move the App in the Home Screen, press when you found the right place for the App.

You can add new Apps (that were installed via the Play Store or preinstalled by Orange) by using the (+) App at the end of the Home Screen (last icon). You'll see all available Apps that can be added to the Home Screen, including the Apps that were previously Hidden.

PS: some Apps can't be hidden, like Settings, My TV, TV Guide and Messages.