I would like to stop breastfeeding. How do I go about doing that?

Various ways. Most slowly omit 1 feed per day. Can rapidly stop and sometimes particularly if child has a more strong temperament a rapid wean/change may be easier - initially more of a shock but quicker for child to adjust. Sometimes if rapidly stop need medications to temporarily suppress milk production. Recommend discuss with wellchild service they're good with this (plunket, iwi or pacific service)
Gradually. New Zealand guidelines recommend that you exclusively breast feed until 6 months and then continue to breast feed but supplement with solid food until the age of 12 months. This is not always possible for everyone and formula is a viable alternative. https://www.huggies.co.nz/baby-care/breastfeeding/stopping-breastfeeding/after-breastfeeding.
You pick. You can drop one feeding every couple days (formula instead) until off. You can allow 2-3 min/side each feed (follow with formula).This signals your body to slow production.You can cold turkey= bind your chest with ace wrap/pre-pregnancy bra and tough it out for a few days. Each of these 3 ways has pro's/cons, in the end only youcan decide what would work for you.Meds are not needed.
Stop It(#EasyAsThat) Dana
A baby suckling is very crucial in the production of milk by the breasts of a nursing mother.
The more a baby suckles, the more the breast makes milk. Less suckling, less milk. No suckling, no milk.
The "last sentence" takes a few days to "kick in".
Also be advised to relieve the very full breasts by expressing slightly if necessary whilst waiting for the milk to dry up.
Best regards.