Oh my, a CVA Optima. They're dangerous. Send me a pm and I will give you my address so I can dispose of it so you don't get hurt.
But if you REALLY want to shoot it you will need primers. Any type of 209 primer will work. Powder. I assume it is a 50 cal so Pyrodex RS should be fine. A powder measure and a short starter. And bullets. Here is a delemia. There is a lot of bullets you can use. I might suggest buying Hornady 300 gr .451" diameter bullets and Harvester Black Crush Rib sabots or (and I can't believe I'm saying this) Powerbelt bullets in 245 or 295 gr.
First thing is to give the rifle a good cleaning.
Now, start with 80 grains (by volume, not weight) of powder.Pour it down the muzzle. Start your bullet of choice or bullet/sabot combo into the bore. Push it in with the short starter then seat the rest of the way with the ramrod. A constant firm push should be all that is needed. Now, IMPORTANT, place a reference mark on the ramrod so you know when the bullet is seated on the charge. (any space between the charge and the bullet can be dangerous as it acts as a barrel obstruction). Next, open the action and install the primer. Close the action and you're ready to shoot. Get in position, c0ck the hammer and fire away.
Also, it is a good idea to get into the habit of blowing into the muzzle after every shot to 'burn up' any embers that linger in the barrel. You don't want to pour powder down a barrel with a red hot ember in it. If you do, you will be in for the surprise of you life. Not to mention burnt fingers, eyebrows, and any facial hair if you got any.
In an effort to determine the most accurate load it is advisable to shoot at least 3 shots with each charge, swabbing the bore between shots. Some guys swab with an alcohol patch, some with Windex and some use just a spit patch. This gets rid of the majority of the fouling from the previous shot.
Now you will also need a 50 caliber cleaning jag, a good cleaning rod, lots of patches and a black powder cleaning solvent, breech plug grease (or automotive anti-sieze) and a quality gun oil.
Please don't wait to buy the cleaning supplies. These firearms can't sit long after being fired as they will corrode in a hurry. Then accuracy goes down hill.
Good luck and welcome.