I knitted these card cases with 3 mm needles (US 21/2), but you can choose the kind of yarn and the needles you want, the size will vary. The gauge is not critical, that’s why I didn’t add it.
The pattern is written in French, Spanish and English. You just have to print, if necessary, the page written in your language and the page with the two charts.
And yes, you can also make the motifs on other projects or cast on more stitches and make more rows to have another kind of case.