Welcome to SRP.

You are fully equipped to create a very shaveable edge with the stones you have. I found the Gokumyo 20k a very comfortable finisher but your 15k may do the trick ?
Of course it will take a little practice but ask any questions & we'll point you in the right direction. You will likely waste a lot of time & have a lot of fun.

I used to have 2 katana & one wakizashi in the 70's but sold them when I bought my first house. Ironically I saw one for sale in the 90's & knew it was one of my old ones. It was a gendaito but I was surprised how little it appreciated in value.