don't need lessons mate just practice, pratice and even more practice. I taught myself how to play electric, acoustic and bass guitar and the best way to do it is just look up music theory, learn chord progressions, keys, song strucure etc etc. Also to get used to how to play the bass look up tabs. Start playing tabs of songs that you like and use these as exercises to warm up (Before writing or playing I would always play a bit of red hot chilli peppers, if your into them learn can't stop, easy bassline and a nice little session starter) Keep on at it and soon enough you will be able to put down a heavy bassline.
