Ok. I found a DwarvenSword in Meshes BSA. When I double clicked it a long list of nif files opened up. I extracted it to my Desktop then loaded it to Nifscope and made the changes I was told to then saved the renamed item to my desktop. Now how do I get it where it belongs to be able to use the item in the CK in my mod? It's such a lot of fun using a totally unknown program with no instructions. I hope I don't kill anything by accident.
You can make a folder in the skyrim data folder for your custom wepaon, or replicate the path from the BSA. Like if the path was "Meshes\weapons\dwarven\swarvensword.nif", you could just make the same folder structure in the data folder. In the CK, the path to models is set like that, and if you have the model uncompressed in a folder, that file will be used. If not, the game will get it from the BSA. So if you want to make a unique item with a different model, create folders in the data folder with the same structure, then put your edited model in there and give it a unique filename, and then make a new item in the CK and in the "model" field and select the new model.