There are several ways you can learn Dutch. If you come from an EU country, you can possibly take a language course at a Regional Training Centre (ROC). Contact your municipality to look at the options.
The course Dutch for beginners is a good place to start learning Dutch for work.
Libraries and language centres also often provide opportunities to practise speaking Dutch.
You can also decide to attend a private language school. This is where you can learn Dutch as a second language (Nt2). You can use Taalzoeker to find a language centre in your area.
If you prefer to learn Dutch at home, you can visit Oefenen.nl (available in several languages) or NT2taalmenu.nl to find out how you can learn Dutch. These online lessons are free.