Because it is a balm-conditioner, the usual place for it is after shampooing. Hair should be damp and squeezed of excess water so the product can spread evenly instead of being diluted. Apply it mainly from mid-length to ends, where coloured hair tends to be drier and rougher. If your roots are oily or get greasy quickly, keep the balm off the scalp and roots; this gives you softness and shine in the lengths without weighing down the top of the hair.
The formula is described as fitting after shampooing when hair needs softness, easier combing and a glossy finish. It also notes that people with dry lengths and oily roots usually get the most benefit from mid-length to ends. Spread a small amount through the lower sections first, then add a little more only if the hair still feels rough. Leave it on briefly, then rinse thoroughly. Because the balm has a light conditioner texture rather than a heavy mask, a long leave-in time is not necessary.
Frequency really follows your washing routine. It can be used after each shampoo while the colour is fresh. If you wash less often, use it when the hair feels rough, porous or hard to detangle. For hair that is very damaged, it is still better to keep it concentrated on the lengths and ends; the scalp produces its own oil, so the roots usually need less conditioning.