The Arcam FMJ 18 spec says it has one MM phono input. Which means that you should plug in the output Left and Right cables of the ProJect into the RCA female socket marked "Phono" on the Arcam, and also connect the ground wire from the ProJect to the Ground binding post in the Arcam. This assumes that you are using an MM cartridge. If you have MC cartridge, you will need the Azur in the chain.
If you choose to use the Azur, then plug in the Left and Right cables of the ProJect into the Azur's input (don't forget ground wire), set the Azur for MM (or MC, as the case may be, depending on which type of cartridge you're using), then plug in the output of the Azur into one of the "Line" inputs of the Arcam (you can use the Aux, CD, Tuner inputs).
Regarding one channel not playing, do check:
1) all four wires are connected to the cartridge in the headshell (at the tip of your tonearm)
2) interconnecting cables from your turntable to the amplifier (or to the phono preamplifier, and then to the Arcam) are alright. If you have any spare cables lying around, try swapping them.
3) assuming you also have a CD source, does it play left and right properly? If yes, then your amp, speaker cables and speakers are working normally. You need to concentrate on 1) and 2) above.
