Numrich Arms has a schematic of it.
It was made between 1934-1946. 100,030 made. No serial numbers. Your best bet is to find a copy of The Gun Digest Book of Firearms Assembly/Disassembly: Rimfire Rifles by J.B.Wood
A Westernfield M72 (actually a M72C) is a Mossberg Model 472. You might try http://www.krausebooks.com/category/firearms_knives for disassembly instructions for the Mossberg 472 in the Gun Digest Sporting Rifle Assembly/Disassembly book.
Go to http://www.krausebooks.com/category/firearms_knives and purchase the Gun Digest Assembly/Disassembly book for shotguns. The Flight King is in there.
Try this site: http://www.gunnersden.com/index.htm.winchester.html They have manuals for the Model 62 slide action rifles. Good luck.
Using of an assembly line increases a production rate and a quantity of manufactured products. Every worker does only one kind of action, so it's easy to teach him (and - if needed - to replace him). Costs of manufacturing are lower.
Your options are: return it to the maker, go to a gunsmith, request a owner's manual from the maker.
The Sears 30/30 lever action was manufactured by Winchester Western.
Belgium
Marlin did not make an 890. but they did make an 89C (often mistaken for an 890) This is a box magazine fed .22 LR semi-auto. If that is what you have, here is a link to a video showing assembly/ disassembly. https://www.youtube.com/watch?v=d1hpc-k28Cg
savage model 25 pump action 22 long rifle
Stock
You need to ask a gunsmith for help