The present continuous or present progressive tense is used to describe what is happening now. For example I am speaking. In English we often use this tense to say what is happening in the future e.g. i am working on Friday. In Spanish this does not happen.
This tense is formed by using part of the verb Estar plus the present participle. The present participle is formed from the stem of the verb plus ando for AR verbs and iendo for ER and IR verbs.