gpt sites

hello friends, I am very new to the whole concept of online earning, recently i joined PTC sites, but i find it very difficult , to sit , for some hours, in front of the computer, and go on clicking. I want to do some productive work, not just clicking..., ...and recently i came to know about these so called GPT sites . i just dont know what are they and how they work, pls tell me about those sites and what are the legit sites..so that i can join ....and can we earn good enough..from these sites...?