Did you read the article I linked to?
http://www.t-nation.com/findArticle.do;j... 05-104-training
Read it, especially #7. Also, stick to the compound lifts to start off: squats, deadlift, bench, rows, chins, dips.
I'm 15, 6' and 185#. My bf% is 12%, which means I have 22.2# of fat on me. The remaining 162.8# of me is muscle, bone, ligament, etc. Find out your bf% and you'll see a better picture of yourself. You can try
www.mybodycomp.com, a scale, or calipers to name a few methods. Know that not all of these are perfect, but you'll get a general idea.
Do you have a weight set to go with that barbell? If not, check out a sports authority, or dick's or modells-you can get a 300# set for like $100. Seems liek a lot, but those 300# lifts will come fast with hard work.
What are your specific goals? If you're looking to add muscle mass, the 4 days of running will hamper that. Don't focus on body parts. Train movements, not muscles. Find a full body routine or try out the one i suggested in the other thread for a few weeks to get aclimated. The compound lifts will add muscle and strength. Do some isolation lifts if you want, but save them until after the compound lifts.
If you have any other questions, ask here or shoot me a PM. Always happy to help