Need API specifations for Sending File

Hi friends,
I am very new to this mattermost environment, and I really need the API specifications for sending files. What are the parameters required and what are those header details for uploading/sending file, and what are those other APIs triggered/associated with the API for sending files "http://xxxx:8065/api/v1/files/upload"? Currently I am developing an android app that will integrate those mattermost APIs. So I need some guidelines and I shall be vary happy thankful if somebody helps me.