First I create HD Wallet using BIP32 using mnemonics.
Now I want to generate new child addresses with private key using xpub & xpriv for every receive.
Then, for example, I received BTC in 2 child addresses, i.e. 3 BTC & 2 BTC.
Now, I have to send 4 BTC to someone, then How can I send it as I have 3 BTC but in a separate account with utxo.
How can I manage these accounts & transactions, and also how can I show the total balance to the user?
So, I don't know how to implement this using bitcoinjs-lib, BIP32.