Bicycling in Amsterdam has become so popular in Amsterdam that in some places there are problems with bicycle parking. Parked bicycles can sometimes block the sidewalk, and cause annoyance and dangerous situations.
There were times that you could basically park your bike anywhere you wanted, but those times are over.

The City of Amsterdam saw itself forced to take measures in certain areas. The two areas that are most problematic are 1. around the Central Station and 2. around Leidseplein.

In these areas rules apply: bicycles need to be parked in designated areas, and if you park your bike incorrectly, it may be removed by the city (transferred to the Fietsdepot).

Outside these areas, there are no real rules for parking a bike. To safely park your bike, it is wise to chain it with the bicycle frame 'to the earth' (attach to a fence, a pole, a bicycle stand, a tree, etc.).
Of course, it is always good to park it in such a way that you do not cause hindrance or unsafe situations.