Not all the features are available in the Mixpanel free tier. You can only filter up to past 60 days worth of data for example. Fortunately, you can use Insights and Funnels, which are great.
Insights is a flexible reporting tool. It has a very traditional UI, which makes it very easy to slice and dice the data. You can even add breakdowns like browser, device and referring domain. You can also choose different types of charts like bars, lines, and pies.
Funnels is another powerful feature. I like the fact that you can build a funnel as simple as two steps. Breakdowns are always present if you want to get a more granular view of your data.