When fitting please allow for some movement in copper pipe to be able to remove filter for cleaning, and when you tighten the Compression fittings onto the filter, hold the end that you are screwing into, if you hold the other end you might over tighten and break the glass.
Use a small amount of PTFE tape on the threads to seal each end, BSPP or BSPT 1/4" threads can be used if changing the fittings as there is. very little pressure.
It is advisable to fit filters before the petrol pump as then you can see debris before it clogs the pump filter.