There are many situations to use -e suffix. Here they are:

1. When it is used, it shows the place of the action and the place of the object. It´s in the element of the sentence that is found when you ask "nerede, kimde" (where) questions to the verb.

Arkadaşları bahçede oynuyor - His friends are playing in the garden

Teyzesi Antalya´da yaşıyor - Her aunt is living in Antalya

Eserleri müzede sergileniyor - His works are on display at the museum

2. It gives the meaning of time.

Tatile Haziran´da çıkacak - She will go on vacation on June

Saat dörtte toplantıda olman lazım - You should be on the meeting at four o´clock

3. It has the meaning of state and condition. It shows how the action is done.

Bulaşıları elde yıkıyor - She washes the dishes by hand

İki saat ayakta bekledim - I waited for two ours on foot