Select the longest chain with maximum number containing functional group OH.
Do numbering so that functional group OH should get the minimum number.
You start numbering from extreme right carbon and goes up to extreme left carbon .
This the longest chain containing functional group alcohol and 2 methyl groups and 1 chloro group.
While writing the IUPAC name put these functional group as a suffix (ol)and substituents as prefix with their numbers and alphabetical order.