Question on pistons

Does the pneumatics kit come with single acting pistons? And how do I code single acting pistons?

Start with the link below for information about the pneumatics kit.
If you have the new kit, you’ll have double acting air cylinders. If you have some of the older SMC air cylinders they could be either single or double acting. Coding is the same for either type of air cylinder.

https://kb.vex.com/hc/en-us/articles/17126345547156-Understanding-the-V5-Pneumatics-Kit-Components

The new kits come with double-acting pneumatic cylinder. Some of the former kits did have single-acting cylinders as an option. The difference is that the doubles will use air power to retract, and the singles will need another force (rubber band / gravity) to retract.

Both are coded the same way - on or off. Programming Instructions

Nope, it comes with double-acting pistons. And for code, there are many topics, so just use the search bar to find it.