The second and the next panels are inserted into the groove of the previous one and fixed in the same way.
You can fix the panels directly to the wall without a frame, then know that this process will resemble the laying of the tile, since the principles of work are the same. At the level of the plinth, we fasten the guide to the wall, which will serve as the basis. Replace the adhesive solution with liquid nails. They are applied to the back of the panel, moving over the entire base, it remains to press the wall and wait for gluing.