Profile times are in seconds (at least as I recall; I agree they need better labeling). Usually, you'll want the "Average" box checked so you can see the average time per call instead of the total aggregated time.

Self time is the total time spent directly in the proc. Call time is the time spent in the proc and any of the procs it calls. Real time is the full measured real time it takes, which can sometimes be a little buggy in some cases I've yet to pin down but can also sometimes indicate certain problems the other two values won't.

Overtime is self-time spent in that proc after the main tick has expired (or more correctly, if the proc finishes when the tick has expired its whole self-time for that call is counted). Overtime is mainly used as a debugging tool in games like SS13 to see which procs are dragging down the server and haven't been accounted for some other way.

The total number of calls is also very useful information, since it will tell you what's called the most often. Procs called most often are your best targets for optimization since a small improvement there translates to a big improvement throughout the game.