For every 1 cup of couscous, you will need 1½ cup of water. So for eg. if you are using 2 cups of couscous use 3 cups of water.
You can add almost all of your favorite veggies in this, though traditionally turnips, carrots, tomatoes, zucchini, butternut squash etc. are used.
I have cut the veggies small to help speed up the cooking to make it under 30 mins, traditionally they are cut into big cubes ( about 1 to 2 inch). Feel free to cut it the way you want but keep all of them in same thickness.
Green chili is optional if you do not like heat, just use the smoked paprika.
Fresh ginger can be substituted with ground ginger powder, add it along with other spices though. Same goes with cumin seeds, can be substituted with ground cumin powder.
Gluten Free eaters, use gluten free couscous (available at places like wholefoods etc.)