I want to post this because I was a bit tripped up for a bit, and after asking a few others, it seems they were as well. There is also no information about achievement rewards in the book. I have had this game for over a month and have logged many many hours during quarantine, mastered 3 classes, and never knew where to get these. I even asked quite a few other level 30’s around the steppe, and everyone said “your achievement rewards should be in your inventory”. I am sure they were a bit confused as to what I was asking, but that just leads me to believe they don’t really know these exist.
For those uninformed: when you meet certain goals, grinding out the dreadfang 30x, mastering a class (lvl30), etc, you will get “achievments”. If you go to your inventory, click on your backpack, and then click achievements at the top, you will find a very long list of possible achievements. It is very likely a good portion of these will be met, and you will have coinciding rewards listed below the achievement. These are typically new titles and new furniture. It is the furniture I had no idea where to go get; heck, I didn’t even know there was a tinkerer’s shop down stairs (there is btw) and this is where you need to go to claim those rewards. In the back of that shop there is another door, open that and explore inside to find the “achievements vendor”. He will have the items you earned for sale at very reasonable prices.
I really hope this helps another like me in need!