support patches update

hi experts

i want to update my support patches..currently my patch level is

sap_basis-70014

sap_aba-70014

sap_appl-60012

guide me for above.

1-from which client i have to logged in with which user.?

2- from which server i have to update( i have DEV,QAS,PRD)

3- from where i can download the patches.

4- which patch i have to update first.

5- what is the important patches which i have to update.

thanks