how to make a helicopter?

first, you need a powerplant. not an car engine from some indian junkyard but something airworthy (read, reliable AND lighweight)

then, you need a transmission and gearboxes. again, NO junkyard stuff.

then, you need fine machinery to manufacture the swashplate assembly.

somewhere down the line, you will need to design the airframe to accomodate the above mentioned components and the fuel and the pilot and avionics.

then, you try to exceed the design limitations while the assembly is tied to ground to see where the structural deficiencies are.

then, you start all over again, learning from your mistakes. and again. and again.

quite a lot of advanced math and computing is involved in there.

You need some professionals. And if you can't get them, you need to study about it. You just can't do it by asking here and making it at home. Either you can buy it from a shop or make it at home. Making at home would require a lot of time and stamina, as well as the right knowledge about it. And if you don't know, don't do it because you'll only waste Time + money + stamina for nothing, so better get the right people or right stuff.

Purchase a properly engineered set of plans or a kit and build it yourself. You might wish to read this: http://www.airspacemag.com/flight-today/Build-It-Y...

Here are instruction on how to make one out of paper.

Go to university, study aerospace engineering, and you will find out for yourself.