I have read the appropriate tutorial and tried several times to use the "Block/Choke" but I must be missing something (besides the obvious couple of screws) because I cannot get it to work.
The blocking part seems to work but never the choke.

Also, is there a way to put the pistol away? Since picking it up, it is always displayed, but I have no ammo for it, so I cannot use it and yet, cannot put it down. Same for the sword, can it not be put away?

Thanks!

To choke, you have to be sneaking and behind the target for the prompt to appear.

To put away weapons, hold down F (PC version).... or whatever the action button is, if you have a different platform.

Thanks! I have been sneaking, do I have to be standing?

No.... usually I'm in sneak mode and come up behind an unaware target, and the prompt appears if I'm close enough.

You have to be behind an unaware target to choke them.

To put away your weapons hold X (360) or Square (PS3)

*hold

I bolded one potential problem. You have to be close, and they can't be suspicious at all. You lose the ability to choke once they get even a little alert.

You also have to hold down the choke button to knock them out.

You also have to be directly behind them, if you're at the side of them it may just show the kill icon rather than both the choke and kill options.

As for the pistol, both weapons are out or in, you can't choose to equip just the blade, would have been a nice touch to use it as a cudgel though when out of bullets, it would fit in with that type of gun as flintlock type guns were designed to be used as both gun and cudgel. You fired the shot then switched to hammer mode as loading was so slow.