RAMPS 1.4 board

Today I'm searching info about my RAMPS 1.4 board

Main source is HERE...
pictures, wiring, and other ingo in many languages
CAD model you can find on GRABCAD

Now I'm understand, that it simply some bridge between  Arduino and stepper motor controllers, LCD, SD card fans, thermistors and other stuff. It powers them, and have some jumpers to set motor microstepping.
Let's look closer...

According to this diagram from REPRAP Wiki

I can attach 2 extruders to my RAMPS 1.4. I like it!) Because I bought two of them.

And I can see, that I need power source 12V with 2 channels. 5 & 11Amps.
Ineed to buy it.

I have D1 and D2 diodes soldered on my RAMPS, and thats meens that I must power it only 12V, and can print without PC.

Useful diagram

All jumpers on my board is set to 1/16 step. And I'll leave it like this.