In French, there is no continuous verb tense like there is in English. So the French present tense, e.g., "Je mange" may be translated as "I eat", "I am eating", or the emphatic "I do eat". Choose which one is appropriate to a natural expression in English. When the French want to emphasize that the action is going on at this exact moment, they may use "en train de" (in the process of). So "Je suis en train de manger" = I am eating. So if in English, you want to emphasize the fact that you're doing something "right now", you can use "en train de" in French. Otherwise, the usual present tense is just fine.
This can be very difficult, even at advanced levels. Trying to figure out when to use de, du, de la, or des is a real challenge! Lawless has information on when to use the preposition de all by itself and when to use the indefinite article, partitive article, or de + definite article (which looks like the partitive - but isn't). For simplicity's sake, here is the information on partitive articles. They are used to indicate an unknown quantity of something, usually food or drink.
- du (singular partitive article, masculine). Je mange du pain = I am eating bread
- de la (singular partitive article, feminine). Elle mange de la soupe = She is eating soup
- des (plural partitive article, masc and fem). Nous mangeons des pommes = We are eating apples. Ils mangent des fruits = They are eating fruit.
Note that the partitive article is often not translated into English at all, but if it helps make a more natural expression in English, you may translate it as "some", e.g., I am eating (some) bread (or) She is eating (some) soup. It is not required and it usually sounds better without. Try to avoid putting in "some" every time you see a partitive article but know that it is there if you need it.