Gardner,
I would argue that the best way to operate a grapple would be to use a diverter valve. This is a valve that allows you to use a function, such as curling your bucket, to operate the grapple. There have been many posts on this subject. The grapple could also be controlled with a remote though. Again, do a search and you will find plenty of info on them here. Either of these can be installed at your dealer, or a competent hydraulics shop. Many people here have installed their own also, but if you are not equipped, and not very mechanically inclined...... i'd probably leave it to a professional.