I bought a starter kit on Amazon and the little breadboard that came with it does have the "channel" running down the middle but the two rows along the outside edge that seem to be where the higher voltage power connects aren't there like I see in other people's projects.
I guess you are comparing your breadboard to this one:
And you are wondering what those additional rails at the top and bottom of it are for.
Well, consider that the underneath the holes there are traces that connect bunch of holes together following this scheme:
It's simple as that. The holes in the middle part are connected together with vertical rails (the black ones) in groups of five at once.
The two horizontal hole lines on top and those at the bottom (both couple of hole lines marked with red/blue strips associated with a +/- sign meaning positive and negative voltage) are connected with horizontal rails. Those rails are generally used for connecting a single voltage supplier to the entire board and sharing it with each component that needs it.
I don't think those horizontal +/- rails are physically any different than the others (the inner black ones), I don't think they can support more electrical power at all. This geometry is being used for making life easier in building prototypes and nothing more :-)
So I'm positive any scheme you find on those tutorials may be ported with minimal modifications to this breadboard of yours too :-)