“Fietsknooppunten” are point locations and “Regionale fietsnetwerken” are regional bike routes connecting these points. Along those routes you can find signs like this:
Where 11 and 12 are “Fietsknooppunten”.
“Landelijke Fietsroutes” are national long distance bike routes. Along those routes you can find signs like this:
You can find more information on the official website: https://www.hollandcyclingroutes.com/