Welcome to the Strelets Forum. Please feel free to discuss any aspect of 1/72 scale plastic figures, not simply Strelets. If you have any questions about our products then we will answer them here.
I have built the guns, which were a bit fiddly, but really enjoyable and look grand once assembled, but not yet attempted this one. It looks 'challenging' doesn't it?
I think that there were instructions on the old Strelets website. The best that I could find was this fellows somewhat step-by-step pictures on his blog (https://minutementoysoldiers.blogspot.com/2015/06/austin-putilov-armoured-car-by-strelets.html).
More useful may be these instructions for a North Star models kit which looks really similar (https://www.kfs-miniatures.com/1-72-russian-austin-putilov-northstar/). I have saved them for my own, later reference.
There was an article on the construction of the kit of the Landships Forum - it really isn't that bad (despite some of the bad press and the PSR article). I constructed three. A fair amount of filler required - it is not up to the same standard as an injection moulded Airfix or Tamiya kit - but I've certainly made worse (for example, before 3D printing became a thing the white metal Revisco St Chammond).