Got the Engine.... now what?



So I finally got my engine which is good bc my car just in dead, never gunna run again! I'm installing it on a mountain bike and so far everything is going ok... but a few Q's.... how do I shorten the chain from the engine to the sprocket? and what is the "Engine sprocket and Clutch Hub
Puller tool" for? Thanks guys!
1) use a chain breaker or grind the tip off the pin and drive it out with a nail for chain

2) it is to pull the engine sprocket or the clutch plate on other side of engine (kinda like a steering wheel or gear puller)
thanks, another Q, do I need to use the idler pulley or if I can get the chain pulled tight can I just not use the pulley?
depending on your frame might need the tensioner for clearance issues. but ideally...if you can install without the idler..whoohoo!
The idler pulley give you a lot of leeway in chain tension that moving the rear wheel won't. Don't make the chain too tight...1/2-3/4" freeplay.

Also don't worry if you don't get the rear sprocket perfectly centered...I don't know if anyone has yet, but turn the wheel and check your chain tightness and make sure you have some freeplay.

I've been running mine with about an inch of freeplay at the loosest part of the run for weeks with no problem.
ok, got the chain on and I looks like its going to work great. Now I'm onto the clutch. I don't get how its going to work. from the point on the engine that the clutch cable feeds through to the clutch arm... the cable isn't long enough. Its too short and heres what I don't get, the arm can't turn that way so how is that cable supposed to do anything?

Does not look like much travel, but it works. What kind of bike are you using? Kind of tricky getting the cable through that little brass thing.
Im using a mountain bike. There is no extra room in the cable. If I try to wrap it around the bike, even loosly, to keep it from hanging where it will get caught, it pulls the clutch. Beyond that, i think the clutch is good to go.