I personally would suggest you to learn about wallets first. Because if you don't understand this, I think it will be a problem. Because a wallet is where you store the bitcoins you have. So don't store the bitcoins you buy on the exchange, because it is very risky. That's why I suggest you learn about wallets first. Then if you already understand about wallets, then you can buy bitcoins on the exchange and send them to your wallet. Also, don't forget to be more careful when you are going to send your bitcoins to your wallet. Because if you make a mistake with just one letter when you enter your wallet address, of course it will result in your bitcoins being lost. That's why when sending bitcoins to the wallet you have to be more careful.
Everything you mentioned are fine but to start investing in Bitcoin, you don't need to know about the wallet first. Initially encourage the inexperienced investor to acquire basic knowledge so that he can simply accept Bitcoin investment and even simply understand. So I personally think that knowing the wallet from the beginning is not subject to basic knowledge. When a new investor starts investing then he will be able to select the right wallet when he gradually become experienced. Moreover, since we are discussing the DCA here, it may be investing through this method, but more can be learned and many things related to investment can be mastered.