1: You will have to make your own manifest. In there you will need to add the necessary aliases, mixinto’s and overwrites (depending on what you are adding). I suggest you take a look at some of the mods that already have been released to see the structure of the manifest.
After that, just zip all the files and make it a smod file.
2: It will be loaded automatically.
these may not address your specific question, but they have a wealth of modding related information (although, some of it is out of date at this point)… so, in hindsight, this might be a complete bust!