The Type is default at free and is locked for now. It will automatically fill the Skin Name and Forma' fields, you can change them if you want. Then click Add to add a new skin to your pack.
If you are creating a new Skin Pack, just click the New Skin Pack, and choose the location and name you want.
Just run the MinecraftSkinPackCreator.exe.
mcpack file so you can install it yourself or export directly to Minecraft. Skin Pack Creator for the Bedrock Edition of Minecraft.