Help please

So basically i'm trying to download a Minecraft mod called All-U-Want, and i've downloaded it as All-U-Want 2.1.jar. I'm on OS X El Capitan. I know you have to copy it to your Minecraft folder in Application Support but I didn't have a folder called 'mods'? So I assumed it was 'versions' instead. When you click Minecraft on your dock it says what version like 1.12 Optifine or 1.7.2 or whatever. So in that 'versions' folder it said all my versions of Minecraft like my 1.12 optifine and 1.11. I thought right away I would put my All-U-Want.jar in that 'versions' folder but then I realised all my versions of Minecraft were in folders? My All-U-Want.jar wasn't a folder so I figured I'd create a folder in the 'versions' folder called 1.7 All-U-Want and put my all-u-want.jar zip in that folder along with my other versions of Minecraft. I thought I did it right when I opened my 1.12 Optifine folder in 'versions' and it had said 1.12.2- Optifine_..._D1.json. The icon of that was a piece of paper along with my Optifine.jar in Optifine folder. And I played Optifine on my Minecraft happily ever after. I'm just wondering where do I get that paper icon D1.json from and maybe add it to my folder for it to work? Sorry for it all being complicated or maybe i'm supposed to name the file a certain name? Please help.