how do I change my Linhof camera lens?

I've never changed lens on my Linhof lens before and now I need to. Currently have a Linhof Symmar-S 5.6/150 Schneider-Kreuznach lens and want to change to Nikon Nikkor-W 150mm 1:5.6 lens. Can I use the same lens board? Do I remove the slotted screws? The lens board has a manual shutter release mounted on the left side facing the lens. I love this camera.

yes.
shouldn't be any screws to remove
https://www.youtube.com/watch?v=l0ebdnhz7e0

Each lens has its own board. If it is like the Crown and Speed Graphics, board holders should like back and allow the lens with the board to be removed.

Check out www.graflex.org and http://www.largeformatphotography.info/forum/ for more background and information.

You may find a manual at http://www.butkus.org/chinon/large_format.htm. Just remember to pay $3US per useful download since this guy supports the website by volunteering.

Are the mount of both lens the same? NO-find a lens board that has a predrilled hole large enough for the Nikkor to just fit through or buy a new board and have it drilled to fit.
Yes- Look at the back side of the lens board combination and using a spanner unscrew the mount ring while holding the lens, remove both from the board, insert the Nikkor, position as desired then secure it to the lens board with its mount ring. You may have to reposition other items on the board to get them to work with the Nikkor or remove them completely and plug their mount holes with light tight material.