To open the membership form, click on the check box next to the PDF icon, then click "Download" on the upper right.  The file should open on your desktop in Adobe Reader, Adobe Acrobat, or your preferred pdf application.  (If it doesn't, look for the file in your computer's "Downloads" folder and open it from there.)  The form is a fillable pdf; tab through the fields to complete the form, then print it and mail it.