This project is simple to assemble using normal household tools and 20-30 hours' time. Use an electric hand drill for drilling string holes in the soundboard and for installing screws. You'll need two c-clamps and some weights for certain gluing steps.
I ordered the hognose psaltery kit to build with my son who is four-and-a-half. It arrived very quickly and everything was as expected. It went together very easily and we stained it a mustard yellow before protecting it with polyurethane. It looks and sounds great.
Few tools were needed aside from a drill, a few clamps and a sander. We made a simple drill jig so the tuning pin holes would be all the same and used a fine flushcut saw to trim the box sides but you could do without those.
Great kit to try out instrument building and gain some practical experience!
We also have the mountain dulcimer kit to try next :)