The boards should be laid in accordance with the design:
position the boards, separating them from the wall with an expansion joint, then press the aluminium slats and insert into them pipes routed to the manifold.
Until we launch the production of slats adapted to the so-called return boards, it is recommended to cover the return elements with flat slats. The required tools include a manual or electric saw to cut (trim) the slats and possibly a manual milling machine to mill the grooves for the pipes at their connection to the manifold or if there is a need to make unusual bypasses.

More information can be found in the downloads: