Yup, its an unrelated t-test, really easy to do (although you need to check your data is parametric first, if not use the Wilcoxon Mann Whitney U statistic).
Not sure how you do it in your package, but its fairly basic. you then get a number (the t statistic) that you need to look up in a table (or its likely that your package will give it to you). Before you start you need to state your alpha level (i.e., 0.05, 0.001 etc) at which you decide to reject your null hypothesis should your experimental t exceed the t under the null.
That's probably not very clear, I'm blatently not a statistion!