I am french and my english is bad

I buy a Mele A1000 this week and i try to do that: http://archlinuxarm.org/platforms/armv7/mele-a100 in section "Installation".
All steps are OK
After, i insert the sdcard into the MeleA1000 and i power on it. The Mele is plug on my TV with hdmi cable
I wait one minute but the screen is always black

Do you know why the boot (on sdcard) not working ?
Thanks you in advance for your response.