Please breathe and relax. :)
Sparkpeople is a HUGE site and there's a LOT of stuff to learn and know. But you don't have to learn it all today.
To get started, just sign in (or right now click on My Trackers - Start) and check the My Goals and Progress section.
You want to make sure that the Weight Goals are appropriate for you. Click 'change' if you need to and reset anything that's needed, and Save it. Eg if you don't weigh much you can't lose 2lb/week even though you can set it. A realistic start is 1% of your bodyweight, or 3% of what you want to lose. See what those values give you.
Then check the Fitness goals. You should have a figure to burn per week. If you're not sure if that's realistic, click 'change' and make sure the days you ticked and the time you said you'd spend working out are correct.
Now, ignore almost everything else.
Near the top of that column is a button for the Nutrition Tracker. That's where you'll want to track your food. Start by tracking 2-3 days, even if you don't change anything. Don't even worry about tracking exercises yet (do them, sure, but don't worry about tracking) until you've got a handle on using the food tracker.
You don't have to use everything and be perfect overnight. Start with just working out what your goals need to be, and how to track what you eat. These are the biggest things you can do to help yourself lose weight.
Deb, in New Zealand