Lowrance elite4x hdi ..... di transducer?

Just finished recarpeting my first boat and just picked up this fishfinder.

I will be fishing in 30ft and shallower lakes.
Any tips or setting suggestions to get the most out of this unit for shallow water fishing?

Any suggestions on where to mount the transducer? (Came with transom mount not trolling mount )

Also, how would i add downscan imaging function? Do you have to run 2 transducers?

This is my first fishfinder as you can probablly tell from all the questions.

You should have the downscan built-in to that transducer.. You don't need another one

Ya its weird, i can switch to downscan images but on the box it said "optional downscan transducer purchase neccessary for downscan imaging"