Let me start by reminding you in a very general frame what kind of information we expect to be able to derive from the observation of stars.
First of all, there are observations - of photometric nature - which allow us to detect the location of stars in the sky. Modern astrophysics enables us, in the general case, to add more or less stringent information on the star distances. On the whole, one reaches in this way a picture of the galactic distribution of stars, i.e. information on the space location.
A second kind of information we can derive from photometric measurements is that concerned with the age of stellar objects. As is well known, this is done - mainly - by constructing HR diagrams for stars which are members of stellar clusters.