Ramset web site specifically says you are not to drive into rock. Rock can shatter causing injury. Ramset has short course on using their product I highly recommend.
Yes. There are several different .22 loads for different materials you wish to use the tool for. Use this chart to find what load you need for your project or you can simply go to Home Depot and read the load box's description on it's use https://www.ramset.com/Portals/0/pdf/RamsetPdrFastener_LoadChart.pdf
If you do want to take the training.... the link is wrong. Instead of https://www.ramset.com/patlicensing, use the non-SSL link. It is still safe, it is just ramjet doesn't support that. You can google or just go directly there: http://www.ramset.com/patlicensing
If your question is can I shoot composite decking into concrete yes but definitely not advisable. My suggestion is to lay down sleepers on the concrete and screw your deck to them.
No! You would be far better to utilize mechanical or chemical concrete anchors.
yes you can, this tool is a great tool and you can do so many different type of work with it and so powerful
Yes. There are several different .22 loads for different materials you wish to use the tool for. Use this chart to find what load and nail you need for your project or you can simply go to Home Depot and read the load box's and nail box's on what is recommended to use for your project https://www.ramset.com/Portals/0/pdf/RamsetPdrFastener_LoadChart.pdf
You should always use treated lumber against concrete. That said I would only use 2 1/2" pins due to chance of deflection the deeper you go. Power of load goes into your calculations as well. Depending on concrete density #3 or #4 load should do.
l would not. Use a pneumatic framing nailer.