Two Questions from a Newbie about a New Gun

I have questions from a Newbie (ME). I just bought a brand new AB Biller 48" professional and it didn't have any documents with it and the LDS said there isnt one and I cant find any on the internet. However my questions are probably pretty basic for any type of gun.

1) What is the best Method / Type of knot for tying the shock cord to the spear gun and spear itself. I see where they tie but not sure what the best method would be.

2) There are two bands but on the spear there are three notches. I figured they have to do with power or speed but not sure which two I am suppose to connect to for best optimization.

Any help any of you can provide would be greatly appreciated.

The shaft slots don't really matter. The further back you pull the more power than bands will have. Since you are talking about lineshafting with a stock Biller you may find it to be alittle underpowered. Make sure the bands are 5/8" and not the smaller 9/16" variety. A simple bowline will work fine but you may well want to go ahead and use 200# Mono instead and crimp it on. Mono is much easier to reload, due to its stiffness it doesn't tie itself in knots when loose in the water.

1) I use a Palomar knot when I tie any kind of line which I plan on using in the water. It's never come loose on me, but can be untied without having to cut it out.

2) It doesn't matter which notches you put the bands on. You may get a little more power if you hook them onto the back two, but they're mainly there so you can use a third band if you ever want to add one.