There are 2 ways that seem to work good for us forum members. No way is a better way its just what you think is better for your chameleon...
You can use the Repashy all in one calcium plus 3 times a week.
Or you can do it old school like me.

Rep cal plain calcium no D3 every feeding
2 times a month one time ever other weekend rep cal with D3
2 times a month rep cal herptivite one time ever other weekend.
This is based on a 4 week month. I will skip the last 2 on a 5th week month. Alternate weekends with the D3 and herptivite... Hope this helps.