I am new to Limewire. I have 2 questions!

1) I do not know how to keep the playlist I have made, or where it goes would like to have a couple of differnt playlists.

2) I downloaded lots of music and have them in my library I have gone to play or listen to songs and find they are a wav ands will not lpy.. can you tel lme why.and if I ned to have mp3 is there away of changing the wav?