Jesper, I email’d a guy I know that uses it. This is what he came back with.
Rub the boiled linseed oil on your project using a clean, lint-free rag, starting from the innermost parts and working your way out. Apply the oil in the direction of the wood grain so that you do no cause streaks when it has dried. Allow the oil to sit on the piece for no longer than 20 minutes, then make sure that you wipe off any excess with a clean rag. When excess linseed oil is allowed to pool on the piece, it can become gummy and ruin your final finish. Allow the piece to dry for at least 24 hours between coats.

Between each coat, lightly buff your project with 0000 steel wool. This will help each additional coat stick to the previous one, and will help create a perfect final finish.

Rub on additional coats of finish. Make sure that you wait at least 24 hours between each coat and remove the excess oil within 20 minutes of applying each coat. Since boiled linseed oil is such a slow drying finish, you will need to allow at least a month for the project to cure if it’s going to be handled or sat on.

I hope it helps
Ken 😉