[What is a "mesh" body?]

Could somebody please explain what the term "mesh" means in second life to me? I purchased a tatoo & i looked up why i couldnt add it to my avatar, but supposedly its for mesh bodies only. I dont understand what I need to do. 

[Why aren't my lindens showing up on my game or on the website?]

So I just bought 800 Lindens, i waited for about 5 mintues then I bought another 800 Lindens, thinking that it messed up some how. I have been waiing for 15 minutes and I still do not see them at all. I checked my bank account and noticed that it was taken out of my accound. Help mee?

[How do I put music in my Linden Homee?]

So I was wondering if anyone could help me be able to play my own music in my Linden home. I went to the About land & media tab but when i try to put the music url in the proper place, it wont play the music. Anyone have any idea how to work this thing haha. Thanksss <3

[How do I 'wear' a VAG... without it going over my clothes?]

Soo I am still sort of new to SL, and i had purchased my first VAG, but every time i 'wear' it or 'add' it, it goes over my clothes? Why is this? Could someone help me outtt, Thankss :)