This is an oxidation/reduction reaction. There are rules to follow and that gives a balanced equation. Here is a site that gives the rules.
Show your work/repost follow up questions. You must work out the oxidation numbers of each element in order to know which elements have changed oxidation state. I will get you started.
S changes from zero on the left to +4 on the right. N changes from +5 on the left to +1 on the right. (Note: A good way to start this is to place a preliminary coefficient of 2 for 2HNO3. That is is order to compare two N atoms on the left with 2 on the right.)