Any input on Transaction Account Builder ?

 Dear all,
I have not worked on Transaction Account Builder yet.

I need some information on that. Is there any document available for Transaction Account Builder ?
SLA User Guide is not providing much information on this.
My basic understanding is that it is similar to Autoaccounting, which is used to populate distributions before accounting is done.
But TAB can be used across applications.
TAB is used for populating distributions and Accounting Method Builder (AMB) is used for Accounting in Subledgers.

I tried to test myself. But i couldnt start because of the following issue:-

I could not create new "Transaction Account Types" in Transaction Account Types window.