The round trip route network consists of a large number of local routes. Most of them bring you back to the location where you started. The length of each route varies between 30-60km. Each route is marked with hexagonal route signs as shown below:
Following map gives an overview of the locations of the routes:
The routes are described in a number of guides,containing maps with the routes drawn into the maps. Maybe a better purchase would be the ANWB Fietsroutebox"". For about Euro 40 you get a box with maps and overviews, containing all info on this network. You can buy them at the ANWB offices, tourist offices and good bookshops.
On the route search page you can click on the buttons with the province names. Press the blue button with the text "Toon resultaat" (show results). It will show then a province map with the routes. Please note, there are two tabs on top of the results page. One is showing a map "kaart", the other one a list with all routes.
Note that also hiking routes are shown!
If you click on a route a small description in Dutch appears. Then you should click on the button "Bekijk details" (View details). Well, it's all in Dutch but at the bottom of the page you may find in which guide the route is described. Maybe you can print the extensive descrition and ask for some help with it.