Hopefully that is thesame or similar o the one required by the OP. When I did a Boschpump there were a few ways that the shaft will fit in and only one way is correct and from memory it has a bit to do with a centre pop mark on mine. Not sure about the Bryce pump.
I would do a search on YouTube listing assembling a Bryce injector pump model

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Or a manual for that model pump. It took me a few hours of trial and error before I woked out how mine worked. So I learnt then to take a heap of pics of everything I take apart, step by step. Good luck with it and let us know how you get on.
P.S. When you do assemble and test it you will only get a small dribble of fuel come out, not some long squirt of fuel.