If you're searching for how to make a crypto wallet, start with this: the wallet does not actually store your coins. It stores the private keys that let you control crypto on a blockchain.
That difference matters. If you lose the keys, you can lose access to the crypto. If someone else gets the keys, they can move the crypto. There is no bank password reset for a self-custody wallet.
A wallet gives you a public address, which other people can use to send crypto to you, and a private key or recovery phrase, which you must keep secret. Think of the public address like an email address and the private key like the only master password that can spend the funds.

