The knife you got you should send back to me so I can take it home. I promised I was going to gift that knife to myself and they ran out before I grabbed one.
Seriously it's a bad ass knife and there's no reason you can't use and enjoy it. There is no rule that you have to work your way up to the good stuff.
As for sharpening I encourage you to try free hand sharpening. I started on the Edge Pro but I don't use it much now since I have way more fun using my stones. You can certainly use the stone you have for now and yes it would be a good idea to add a finishing stone to the set. Something in the 4-5K range would be a good choice. I like the Imanishi 4K and the Suehiro Rika and either of those would work well for you.
If you have questions on sharpening please watch some of my videos and then come back and ask questions. There are lots of good sharpeners on this forum that will be happy to help you.