If you have the smaller container in the cage, she should start digging in it. Once she is intent on digging a hole (but not when she is actually digging it) you can move her to the larger container outside the cage. However many chameleons will lay them in that small sized container in the cage.
Here is how it should go...female becomes restless, will likely drink more, may eat less, should become fatter in the back end, may show egg bumps just near the back legs, likely stays dark color.
She should then start digging a hole in the container. (You should not let her see you watching her when she is digging or she will abandon the hole and if it happens too often she can become eggbound.) She may dig one hole or she may dig more than one but should chose one in the end and dig it until she is happy with it. It may take one day or it may take several days. She should then turn around butt down and lay the eggs...likely in the evening. Once she has laid all the eggs she should fill in the hole and tamp it down and return to the branches, hungry and thirsty.
If it does not go like this, then please post to let us know so we can help you through it.