How much extra ingredients can I add to the rice without them being undercooked?

I got a 400W ricecooker a while ago and this is my first time encountering such a gadget. Where I live they usually only use them in restaurants.

I am planning on putting some rice, frozen prepacked vegetables and some thinly cubed chicken or ground beef. It only has a cook option that automatically switches to warm when the rice is cooked (no water), and no other options.

How much vegetables and meat can I put inside without them being undercooked?

Will the water to rice ratio still be 1:1?

Will the ratio of rice to other ingredients matter in this case?