If Rotary is new to you, there are a number of sites which will tell you more about what it is and what it does. The best place to find out the basics is at the official Rotary International Web Site.
If you're in the UK or Ireland, the Rotary in GB & Ireland Web Site.
From these starting points you'll soon be able to find many other interesting Rotary related sites of all shapes and sizes around the world. Why not look one or two of them up and see what's happening elsewhere in the wide world of Rotary International