sry bout the newb question but...
 

I bought a Mongoose Sniper Frame off ebay recently. I am building this bike from the ground up. I was going to use this one-piece crank from another bike i have.. everything would have working fine cept the wheel was rusted on the crank so i couldnt remove it.. the crank was tubular and it had threads on the oposite side the sprocket was on. The threads secured the whole crank on.. Now i bought a forged one piece crank.... just the crank arms no bearing or nething. there are no threads on this one... How do i put it on there? will i be able to use the bearing from the other crank? what els will i need to buy? thanks for anyones help in advance,
~ Chris