The Olaf build for Top is Sterak's Gage, Experimental Hexplate, and Ravenous Hydra. This LoL Olaf guide for Top at Platinum+ on 14.3 includes runes, items, skill order, and counters.
Olaf Counters
52.7%
(-0.2%)
54.1%
(+0.9%)
2.3%
(+0.1%)
2.1%
(+0.2%)
846
(+11)