First things first, RTL.

Take the bow to a bow shop and have a skilled person examine the bow for twisted limb(s) and condition of glass on the limbs.

Have a new (Dacron) string put on the bow.

Do not use those wood arrows if they a very old. You could end up with a broken shaft sticking out of your bow arm.

To select the correct spined shafts, you have to know the poundage @ what draw-length to know what actual draw-weight you will pull, and your draw-length. Most likely, that Griz is a xx# @28" draw. If your draw-length is shorter than 28", you have to subtract poundage. If your draw-length is longer than 28", you have to add poundage.

Unless worn off or painted over, somewhere on the riser section or a limb you should see the specs of the bow. In writing, the marking will look something like "AMO 58" 55#" which means that the bow is a 58" bow and has a 55# pull at (probably) 28".

Once (if) the condition of the bow is found to be in good condition, have your draw-length established. This (draw-length) is usually done on a very light draw-weight bow that most archery shops have. However, I advocate that a person's draw-length be established on the bow the person intends to match (length) shafts to.

Also, if your draw-length is much greater than 28", and the bow is a short bow (56" to 60"), the bow may "stack" on you, which (stack) means that the bow will pull hard to a full anchor.

Since you are still in the novice stage, I recommend shooting aluminum shafts.

And that is just a very, very, small tip of the iceberg as you become a "shooter."