maxkd

Ok i am totally new to the electronics game but fascinated also.Can any wiz kids help me build the following in the most simple idiot proof way(so i can understand,yes im an idiot) Project:want to build battery operated voltage generator with following specs! 0-30 volts(variable) polarity changes automatically approx 4 times a second 0-50 milli amps(variable) flowing thru to attached electrodes. I have seen similar projects elswhere but they were more complicated and too advanced for me at this stage. Would really appreciate any instructions,diagrams again in an idiot proof form!