Model Railroading > Installing new decoders in BLI locomotives

I'm a total novice at this, but I bought a new steam sounds decoder and a keep alive that I plan to install in a BLI steam engine and add a keep alive.  If all goes well, I will be converting more, as I find most BLI steam to have pretty low quality sound.  Does anyone know of a good and fairly simple online step by step guide on how to do this conversion.  I've watched YouTube videos, but my complaint is that most people go all the way and essentially rebuild the engine, replacing everything, removing smoke units and changing out the headlight.  All I want to do is take the old decoder out, put the new one in, (maybe replace speakers eventually).  The videos are great, but they are so long and drawn out, and I don't end up getting much from them, except that I really don't know which wire does what and how to make sure my new decoder connects to the right wires.  Does anyone know of a guid that will explain exactly how to do this without all of the extra info?  

Note:   I don't want to pay someone else to do this, because I want to learn the skill so I can upgrade my own equipment, but I'm a novice and don't want to ruin my locomotive. 

The various Kalmbach books start with basics. I think they're a good investment ( new or used ).
Lots of internet sites that cover basics. MRH online magazine is a source.
I find it easier to learn from printed material than YouTube videos.
Bill in Ft worth

 

This is an excellent video on installing Soundtraxx into BLI.   Step by step easy to follow.

https://www.youtube.com/watch?v=lxoS-Qlgodg

Mike Stewart
Oakley, CA

Thanks guys! this is a good place to start