Inverse and Logarithm????

well need help...
I kind of know inverse one of the examples for inverse would be
Inverse of f(x)=2x is log2x you cant plug the x on top of the 2 but x supposed to be on top of the 2 and in the log, the 2 in the bottom of log and the x is in top of the blog. sorryyyyy..hope you understand it.
but I still have trouble graphing logarithms
Help help.!!!!