I don't know how to change the ink in Canon mp600

not enough info.
Have you bought new carts yet?

What type are they (No on cart.)

Switch on the printer. Open the front output tray. Lift the lid and the glass platen. The ink cartridges will slide into view and be lit up in red. Any ink needing changing will be flashing.
Press the white handle to release the cartridge. It will stop flashing.
Tilt it up and pull towards you to remove. Remember how you do this as the new one needs to go back in the same way.

For the new cartridge: -
Open the packet and peel off the orange protective film.
Carefully remove (twist off) the orange protective cap.
Do not touch the electrical contacts on the cartridge.
Do not shake the cartridge.

Insert the new cartridge in reverse to how you took the old one out.
Push it down to lock it in place, it will light up when correctly inserted.

Close all the covers and dispose of the old cartridge safely and responsibly.

Here is a link of a video showing you how. Hope this helps.
http://www.youtube.com/watch?v=XyT6JsD0o88

Hi
I can not seem to put my ink cartridge to fit or slide in