Cut the melon and remove the seeds before cutting the meat away from the shell and put it in the blender. Add the lemon and lime juice and a little bit of sugar. Don't add too much sugar straight away. You can always ad more later if you want.
Turn in the blender until everything is nice and smooth and taste if you like the sweetness. Add a bit of lemon or lime if it needs some extra acidity and some extra sugar if not sweet enough
Put in the fridge until ready to use.
Add the blueberries together with the vanilla yogurt till a smooth mixture and again taste if it needs anything. Also check if the mixture is thin enough to pour into the popsicle molds
If you have a regular popsicle form, first add one layer, let it freeze and than pour in the other layer or just do it all in one go. It will be good no matter what.