There should be a dipstick which measure transmission fluid level. on the stick there will be marks indicating ADD (meaning you nedd to add 1 quart of fluid [.9 liters]) and FULL.
With the engine at normal operating tempeature, move the gear selector throught all of the gears and then back to park. pull out the dipstickand wipe it clean. re-insert the dipstick and pullit out a second time and look to see where the fluid is on the stick. add fluid accordingly. If no fluid is touching the stick this means you need to add at leaset two quarts of fluid. [1.8 liters]
Please let me know how it goes.

Also most full service stations (petrol stations) will have an attendant who can check it for you (free).