How to find critical path, free float, total float

ES(Early Start) = The earliest date activity can start
EF(Early Finish) = The earliest date activity can finish

LS(Late Start) = The latest date activity can start without delaying project completion date
LF(Late  Finish) = The latest date activity can finish without delaying project completion date

(D=duration)
EF = ES + D
LF = LS + D

Free Float/Path Float/Slack = LF - EF
Total Float = LF - ES - D