Firstly have your note book and sheet of card, to cover an A6 notebook you need A4 card so you need to scale accordingly for your notebook.
Cut your cardstock so that it is just taller than the notebook and twice the width plus at least 7cms (this is where i move slightly away from the Dutch instructions) Then score at the centre point and 1cm either side.
You should have 3 score lines across the width of your card, bit difficult to see in the picture (the help of a cat is optional)
Fold on the centre score line and then cut from the edge to the next score line at two points equal distance fron the ends, I cut 5cms from both ends.
You should have two cuts like this.
Glue the folds together
This is an adaption I mde to the original as i think it makes it a bit neater. place your notebook in the folder you have made and score alng its edge, remove the book and score about 3mms further along from the score line just made, this can then fold over the edge of the book.
You can now glue the notebook to the back cover and spine, i recomend very sticky glue and using somthing to hold it together while it sets.
Repeat for the front cover and leave for glue to dry.
An example of a finished book, in this case a diary.
I hope this has been helpful, sorry aboout the awful layout I can not get it to behave :)