Abstract: A method for mounting a seabed installation including a drilling template and a manifold on a mooring device anchored to the seabed. The mooring device comprises an open guide boring. The drilling template and the manifold are arranged to be suspended separately on, and lowered by a string which extends from an offshore platform. The method includes lowering the manifold and inserting a connected guide post which projects down from the manifold, in a guide hole of the drilling template. Thereafter, interacting sections of the central guide post and the guide hole respectively are made to cause an alignment of the manifold in a fixed rotational position relative to the drilling template during the introduction and before the manifold comes into contact with the drilling template. Finally, the manifold is lowered relative to the guide post after the contact thereof in the guide hole. No use is made of guidelines which extend from the platform to the seabed.