Being new to BTC I would like to know where the BTC are held that are for sale?
The coins that are on sale on exchanges can be bought like an asset but they are stored on the blockchain not your wallet. What you have control over is your private keys which can be used to spend those coins. Who has access to your private key has the power to spend your coins.
I am learning as I can understand a complicated subject the deeper I dig into BTC. My stepson is a BTC bull, and he says I need to spend 1000 hours to understand BTC?
Ok, now this is cringy as f*** - without further context, I will not comment.
Other than private wallets, is there a pool of BTC, and how many are there of the 21000000 total available?
This you can google and find out. But this is not really relevant to the title.
I am looking to buy more BTC ETF before I go deeper into buying the actual BTC wallet.
Ok let me get something clear
1. Anyone who is trying to "sell" you a "wallet" is scamming you. Do not do that, you can buy bitcoin on your own, and that is the only safe method to owning your coins second to earning them.
2. ETF is not same as owning BTC. Just like gold ETF vs real gold.