To move around the gallery please click on the arrows on the floor. You can get closer to the paintings using the top arrow. Notice that this feature is disabled on small screens.
If you'd like to know more about a painting, click on the title under it. From there you'll also be able to visit the page dedicated to the artwork where you can read all details.
And when you are ready to leave, you can exit by clicking on "EXIT" at the bottom right corner.