I am working on a power supply project and I am using LM338 regulator (metal case) but I am finding it hard identifying the configuration of the regulator.
check the connection diagram in the datasheet, clearly explains you which is input and adjustment pin.
I have attached a jpg image, open it. the two pins which are input and adjustment is not located exactly at the centre. they are located somewhat closer to one end of the output pin. And, comparing with the datasheet, from the bottom view, left side pin is adjusment and right side pin is input. Make sure, these connections are from the bottom view
You dont need to try something to see is this simple or complex. But observer knowledge will decide on which side is design, simple or complex, and expirience you will get with practical working.