How do you install this band on a samsung active if its not quick release?

Its comes with a prong tool to set the springs.

how lone is the watch band? I have a small wrist.

The length of the strap varies with the width of the strap. The specific dimensions are shown in the third image. Band width 14mm :The length of the wristbands is 2-9/16"(65mm) and 4-17/32" (115mm)without buckle.Designed to fit wrists 5.5" to 7.5". Band width 16mm : The length of the wristbands is 2-61/64"(75mm) and 4-17/32" (115mm)without buckle.Designed to fit wrists 6" to 7.5". Band width 18mm: The length of the wristbands is 2-61/64"(75mm) and 4-59/64" (125mm)without buckle.Designed to fit wrists 6.5" to 8". But watch dial also impacts fit. If you are not sure if the strap length is appropriate, contact us and we will give you a suggestion.

do watch bands come with spring bars

Yes, this watch band come with 4 spring bars and a replacement tool.

Difference between fm18-20-22zk3 and 22zk2?

use the links that comes with it, thought I could use the originals but they werent long enough, took the old ones off, inserted the pair that came with the band and WaLa, fits perfectly, looks original to the band I replaced