You can do it yourself....But
if I were you, I would have a rigger do it, if the boat is >10yrs old you should replace the fore stay, I just had one put on my H33 and the rigger charged $400 for the install and a $100 for the stay, took him 1.5 to 2 hrs. Ask yourself how much your time is worth, I figured it would take me just about all day, so to me, my time is worth the 5 bills, and there is piece of mind with a pro. while he is there ask him to inspect all of the other stays/halyards and rig (he won't charge you) and you'll know what is safe and what needs replacing.Just my opinion,Greg