The present tense is pretty simple in German: there's only one. So where English has to choose between Sarah is walking to work and Sarah walks to work, German has only Sarah geht zu Fuss zur Arbeit. However, whereas English only has two different forms of each verb in the present tense (apart from for the verb to be), e.g. walk and walks, have and has, German verbs have lots of different forms in the present tense (typically four or five), depending on which personal pronoun you're using. (Personal pronouns are words like I, you, we and they.) This podcast explains more about the present tense and the different forms the verbs you use in it take.
To listen to the podcast on you computer, click here.