Egbert.
The first two boxes, next to Mapbox 1. The first box is for the ID example: "tomtit.gof32s" in the first box. The second box to the right the Key example "pk.089y4gf92bnf0u2g3r4021093uhf0fh"
Then close Plan G. Next reopen Plan G and check options general to see that the bullet (dot in the circle left of Mapbox 1) is next to the ID and key boxes where you have entered the information. If it is go to the home button and the newly selected map should appear. I hope it helps.
Wings
The first two boxes, next to Mapbox 1. The first box is for the ID example: "tomtit.gof32s" in the first box. The second box to the right the Key example "pk.089y4gf92bnf0u2g3r4021093uhf0fh"
Then close Plan G. Next reopen Plan G and check options general to see that the bullet (dot in the circle left of Mapbox 1) is next to the ID and key boxes where you have entered the information. If it is go to the home button and the newly selected map should appear. I hope it helps.
Wings