Hi and welcome to SP. You can add a tab to your SparkPage that says your looking for a buddy. I believe you need to go to your account page to dop that. Not 100% sure but you can also go to the message board and post the question under the techical questions topic and you will get a fairly quick response.
Learn to navigate the site and read as much as you can to learn to make the lifestyle changes that will get you to your goal. Remember it's a lifestyl;e change not a DIET. Changes take time to take effect. Most important to know is Small Goals and Small Steps = SUCCESS. Keep in touch with SP make friends, join teams (not too many now) and read, read, read and learn, learn, learn. If you knew how to do it you would have down it by now !!! Best of luck to you.