HI u can have the directory structure like this,
------------------proj-------------
|
|-------<PROJ CODE>
|
---------docs
---------netlist
---------rtl
---------sim
---------synth ------|<scr>|
|<reports>|
|<db>|
---------tb ( testbenches)
---------sdf (timing simulation)
--------- test
--------- make
---------sta
---------release