Hi, Bryan. First of all I would like to welcome you to Pakwheels.com and welcome to the Belta owners and fan club aswell. I see you have a Belta, what varient is it? If I may ask could you post some pictures of your Belta? I hope I am not becoming to personal.
As far as the CVT fluid is concerned, it should be changed at every 60,000Kms. Are you facing any problems with your transmission? Is it giving you any jerks or it is acting strange in any way? If your Belta isn't driven 60,000Kms yet or isn't giving you any types of problems and it isn't acting strange I suggest you don't flush/replace your CVT fluid yet.
If you still want to flush/replace your CVT fluid what you will have to do is, turn to open the drain bolt of the gearbox a little not all the way or your transmission fluid will just pour out within seconds. Turn to to open the drain bolt a little and check the color and the stickiness of the fluid if the color of the fluid is dark green and it's sticky, it's time for you to change and flush the transmission fluid.
The best CVT fluid for Toyota's is Toyota Genuine CVT Fluid TC you would need around 4 liters for a complete flush and replacement.