Quartus Compilation Report

hi, im trying to get myself familiar with altera quartus but there is a few info that i dont understand.

on the compilation report on this fitter summary, im not quite sure what is the total pins means. i realise on one of my project file, it use up 513/622 (82%) i wonder it is so much and what does it means.

also , on the timing analyzer summary(classic) what does worst-case tsu, worst-case tco, worst case th means?