What don't you understand.
The OP cannot use income method.
He is Oz and that embassy does not provide income letter.
On top of that he does not even have a bank account showing 12 months of transfers.
He needs to use money in the bank method.
Furthermore entering visa exempt he will need to open a bank account and that will not be simple.
I met with Maneerat (Pattaya) on Friday and bank account is ~5k with BBL.
The OP is best advised to obtain non O in Australia. With the non O he may be able to open Thai bank account in his name only.
Kasikorn have done this without certificate of residence.
As soon as he opens bank account he could start monthly transfers 40/65k in preparation for second extension.