I've lived for 9+ years outside The Netherlands and was never allowed to vote. I'm excited that things are different in The Netherlands and many expats can vote here for the upcoming local elections on March 19th! Below some info that may be helpful:
EU Nationals: you can vote for District Committee and City Council if you are a registered resident of Amsterdam aged 18 or above
Non-EU Nationals: you can vote for District Committee if you have resided in The Netherlands for at least three years and for City Council as well if you have resided in The Netherlands for at least five years.
You should have received a voting pass (in Dutch...) in your mail. You can use this to vote on the 19th.
For more information you can look on the government website: Protected content
I'm fan and member of the VVD. More information about the VVD can be found here: Protected content
Most important: you have a vote and there are many expats in Amsterdam, so let your vote count!