It is vague because it depends on each case. Any case I know of they look for confirmation of 'yarn', so they may write to employer for confirmation or look for any other proof they want, while a person may get SW from date of leaving it is unlikely to be issued immediately so either you have savings to live on until they decide or supplementary welfare if no other supports. If they do approve from date of leaving you will get the backdated money but just may not have anything until it is decided.
Disqualification period could be up before decision is made.