Press the plastic mesh tube gently together and place it inside the gutter. The slit has to face downward. The tube holds itself in place between the gutter and the roof overhang.

If the roof does not have an overhang, the tube should be additionally fixed in maximum intervals of 1 m.
Cut out openings for downpipes.

Remove the sieve in the downpipe.
Make a mitered cut in corners.
To prevent birds from nesting inside the tube, close off the ends by folding them under.