STATA PANEL REGRESSION DISCUSSION

need help figuring out a few things in my panel regression data. want to ask whether you know how to test hausman in the case of xtscc comand. have autocorrelation, hetro issues as well codependence. Know how to run the comment. Want to know how to decide between fixed and random for xtscc command. also when do we introduce fixed time effect in the panel regression model. I working knowledge of stata and am open to a discussion to find out the solution.