new blogger still finding my feet

I set up this blog originally for people all over the globe to offer practical and affordable ways of easing toothache pain. Investigating further I have realised that I can place non-obtrusive ads for dental and painkilling treatments, hmm i thought that must be easy but of course with my limited technical abilities it has taken me 8 hours to place one ad jeesh. I know that I am allowed 3 ads but god knows how you do it? If anyone has an easy step by step dummy guide please please let me know...