A .jar mod?

Hello,

   I am yet not completely finished with my mod, but am waiting for further information on how to accomplish a last and final step. Still, I wanted to see what would happen when I export the mod (as I wait for further information for this last step), and saw a .jar file produced.

    This is my first time working with exported mods. Where would I have to put the .jar file (for it to operate under my regularly purchased version of Minecraft)? How would I turn the mod that I made on or off?... and how does it all work? Is there also a way I could put finished my mod online for others to download (after it is finished)?  Thank you.