23M investing in bitcoin

Hi there,

Not too familiar with the bitcoin scene, just know I should be atleast starting to invest it in sooner rather than later.

Income is roughly around 105k NZD per annum. Usually save roughly 2-3k per month after expenses. Single no kids, renting on my own. I already invest into a hatch account which has a portfolio of 1k in eft’s etc

Couple of questions:

1) where do I buy bitcoin

2) how much should I realistically be buying every week/fortnight/ month. Not trying to beat the market as in the long run it will increase (hopefully)

3) thanks