Bones: I use whole chicken carcasses (after using the meat for meals) for the sake of being economical. You won’t get the best gelling broth this way unless you reduce the amount of water you use or add extra, more gelatinous pieces like chicken necks, feet or wings.
Concentration: You’ll get the richest broth if you just cover the bones you use with cold water. You can add more water if you wish (never above the max fill line), but be aware that you won’t get the best gel, if that’s important for you.
Frozen bones: I save bones from meals and collect them in my freezer until I have enough for a batch of broth. You can use entirely frozen bones in the Instant Pot, but be aware that it may error out, failing to reach pressure, because of the lowered overall temperature of the Instant Pot contents. If that happens, simply reset your Instant Pot: it should seal on the second attempt. This will add a little extra time to your broth making (about half an hour), but otherwise won’t affect the outcome.
Sediment: I find that I still have a very fine layer of sediment at the bottom of my broth after using a mesh sieve. I don’t personally mind this, since I use my broth primarily for blending into large batches of vegetable soups. If it bothers you, you can either run your broth through a fine mesh sieve or cheesecloth again, or simply not use the very bottom of your broth.