How To get Address Public Key from Account XPUB? I am little bit confused or not able to get the right Address Node Public key from Account XPUB.
What I have done :

Get the Account XPUB [78Bytes]

SHA-256

SHA-256 Again

Created Extended XPUB (XPUB + 4 Start Byte of Step 3)

Base 58 ENC

hdnode_deserialize()

Account Node  Change Node

Change Node  Address Node.


But am not able to get the right Public Address.
Please let me know if I have done something wrong.
To go from account xpub to address, you must first derive an xpub at the External index (0) or Internal index (1), then derive another xpub from the External/Internal xpub. Take the public key from the resulting xpub and this is the public key used for the address.
For a detailed explanation of extended public keys and how to derive child public keys, take a look at the BIP32 documentation. For a not-as-in-depth breakdown of deriving addresses from an extended public key (which is exactly what you're trying to do), I have written this writeup.