You can create your own metadata schema from metadataschema editor available OOTB. And apply that newly created schema to your dam folder.You can drag and drop widget , create what metadata you want for asset and save.
To apply to specific dam folder you need to add metadataSchema="path-to-your-custom-schema" property to that folder.
Please note that this newly created schema will be stored under /conf/global/settings/dam/adminui-extension
For creation of metadataschema you can go to below path