benefits and self employed

Hi

Im looking to maybe start a small selling business over the internet after christmas, and im currently on IS and registered as self employed hairdresser, but i cant hairdress anymore due to problems with my hands, so they put me on IS because I cant earn and dont want to claim Disability because I can do other things rather than hairdress, but what do I have to do to turn this idea into a legit business

I have two children so im scared of taking the plunge and coming off IS incase I cant earn enough etc is their any help or anything or anyone know what im entitled to earn before having to declare it? or just any information I may have missed

When I went self employed previously I went from full time in a salon to self employed mobile so I have no idea what the transitions like from benefits to self employed

any advice anyone?

many thanks