Hi Michael,
Just follow your RACOR manual (by the way, it is a RACOR brand filter, not a RAZOR filter) and that will tell you to unscrew the "T" bolt on top of the housing, remove the top, take out the old filter, insert the new filter, top off the bowl with clean diesel fuel, and then put the top back on. Very straightforward. Of course, having opened the fuel system you will need to bleed it before running the engine, which will also bleed any residual air from the RACOR filter housing. And Bob's your Uncle.
Cheers, Craig