help setting up unit

hello all, i am new to site an in need of a little help. here is my situation, i upgraded my radar to the new 6kw digital with the tzt2 12 in touch screen an love it, but i got a rd149 navnet 10.4 in screen used unit from a buddy an installed it as a stand alone fish finder. i need help in setting up the unit, basically how to reset the unit so i can start over. All i want is the unit to read the depth of water, from 5ft at slip to 3000+ offshore also to show thermal change an mark fish,,,but i just dont know enough about the unit to set it up?? thx for any help.

Did you get the RDP149 with an external sounder module? If not it will not be a depth sounder.