I used to build a Wire strung harps of my own design. I have one, 29 note, pictured in my album. I also made 19 note model that was a nice lap size. They were very simple and w/o sharping levers. The first 3 harps I build did not fly, so to speak. It took a great deal some experimenting to get a balance of all the things I wanted in the instrument, so I have to admit that I am somewhat self taught. For the neck and support member and body, a tight grained hardwood, well seasoned, should be used like Maple or Cherry, and it should be free from windshake and any defect.
I knew a harper that laid out $2300 for a custom Welsh tripple strung. The beams were Oak and the thing broke apart apart on stage while he was performing.
My favorite wood to work with is Cherry. The color gets richer with age and it has the feel of living stone when finished right. The sound board is very important also. Sitka Spuce is in my opinion the best clear cedar can alsobe used. The growth rings should be 20 per inch or more. At the time I was making most of my harps and hammered dulcimers I worked at a piano shop that gutted fancy old English pianos and put in new back plates and actions. I would get all the old sound boards out, wich was extremely laborious. All my instruments had a sound board that was allready 120 years old! I think it was worth it, as it added a magical sound to them. good sound board wood is getting harder to come by and most of there inexpensive harps use plywood in the soundboard and body which seriously effects the tone and character. In a wire or gut strung harp, scaling of string length/diameter is the most important factor as this is the heart of the intruments character i As the notes go higher the length of the string gets shorter but also the diameter gets smaller by thousandths of an inch. That minute change will effect this character greatly. In wire strung harp, I use tempered brass string on the first few low notes. The brass gives a much more brilliant tone at a lower tension than steel in that range.
One thing a seasoned old harp maker told me was to make the thing so its about ready to explode, which means to stress the frame to its limits. I have found in the harps that I have made is that they sound better as they get older, because the stress reshapes the body and crowns the soundboard overtime improving its accoustics,
My advice to you, Semira, is to get a kit. Lark in the Morning I think has some good kits. Usually the materials in a kit are somewhat inferior but it will give you some valued experiance and basic knowledge you can use to design your own