How to build a dc to dc converter?

Need help building a dc dc converter that takes 10 - 18 vdc @50amps. Out put 50vdc. I found an uncomplicated schemattic for 1 that only consisted of 2 mosfets 1 torrid 1 bridged diode rect. And 4 filterring capacitors but no values and didn't show how to wire everything together. And is it possible to wire multible together for more amps?
 
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