Controlling 4 high power 10w LED's with adafruit motorshield v2

I have an setup where i have 4 x 10w LED's hooked up on a relay and one click button.

click.. led1 lights up
click.. led2 lights up
click.. led3 lights up
click.. led4 lights up
click.. led1 shuts down
click.. led2 shuts down
click.. led3 shuts down
click.. led4 shuts down

But i need to get rid of this relay clicking noise and have a motor shield laying around.
So i would like to use this instead of relay's
but with a little of trick - not click on the button and light is on, but i would like that after an click it takes about 2 seconds until the led is on full brightness (PWM(dimmer)) and when i click to shut down the led it dims off.

But i have no idea how to code this.
So i would like your help.

Sorry for my bad english