Carb Retune + Oil Leak Questions (2004 Suzuki Katana 600cc Manual)

I'm thinking of buying an old 2004 Suzuki Katana. The owner says it needs a "carb retune" and has some oil leaks. How difficult would it be to do these fixes as a beginner (I've not really worked on anything before). Any tips or instructions doing these things? What tools would I need? Thanks in advance?