No, you don’t need a printer. All the worksheets are “clickable,” meaning you can write on them from your computer without printing them.
The only worksheet that’s not clickable is your smoking notebook. You can transfer the columns of the notebook to a real notebook or the notes app on your phone.
Note: If you want to do your worksheets on your phone or tablet, please download an app such as “PDF Expert” or “Adobe Acrobat” that allows you to edit PDF files. If that’s not possible, you can still use any physical notebook to write your answers and exercises.