Can someone point me in the right direction on getting more info about reading my depthfinder?  I have a Garmin Echo 150.  I know it is very basic, but I still need some help in terms of how to interpret the screen, how to set it up, how to know where the objects on the screen are in relation to me.  I have a kayak and the transducer is mounted in the hull with that putty stuff that I cannot think of the name at the moment??? Any help would be appreciated.  Thanks!

Youtube has a bunch of videos. They may not have anything specific to your unit, but reading/interpreting most graphs is pretty universal. 

Thanks fellas