I really don't know what is the name of this plant .... and How much should i water it ? see the attachments.
I am not sure but it looks like a succulent. More specifically it looks like it might be a type of crassula. A crassula is a type of succulent (jade plant is a crassula). Succulents like sun and not a lot of water. Succulents need water when in active growth (usually spring and summer) and little or no water while dormant (mainly in winter). In spring and autumn water plants every 1-2 weeks. In summer allow the soil to nearly to dry out between waterings. In winter water sparingly from tine to time to stop roots from drying out. This is from a book I have on cacti and succulents. Over watering is a common problem. Maybe someone will be able to be more specific.
Kalanchoe blossfeldiana. It is normally purchased in flower, then treated as a throw-away when the flowers are spent. Good cultural information here.