En la descarga, que he realizado, no está activa la funcion de imprimir
Hello and welcome to the Seamly2d Forum, @KEKARO
First you need to create your pattern from your draft using the Piece tools. Then you may go to the Piece board to add seam allowances and notches, etc. And then you may go to the Layout board to generate your pattern.
Once you have generated your pattern, the Print will become active.