Well first of all it's called photosynthesis and this process consists three things water, sunlight and CO2 (carbon dioxide.)
So we receive the carbon dioxide from the air.Our leaves absorb it through our Stomata. These are pores that we have in the lower part of the leaf.
How the light gets in us and helps us is like this, our cells are inside chloropasts and chloroplasts also contain a green substance called chlorophyll. The chlorophyll absorbs the lights energy and that is why the plants are green.
know we plants cannot do photosynthesis in the dark because there is not any sun. Photosynthesis creates glucose and oxygen and the oxygen is released and the glucose stays inside as its food.
We plants to drink water we get it from under ground from our roots and that is called a vascular plant and what a non-vascular plant does is it gets its water from its own body because the non-vascular plants have tiny holes in them but that is not my case I am a vascular plant.