Should I get lean before trying to add muscle mass?

No it is a waste of time to do that, you can gain muscle and lose fat at the same time, don't worry about supplements like creatine when you first start trying to add muscle, creatine is for more advanced users who need a kick in their routine to boost there lifts. When you lift weights it tears muscle tissues, which your body needs to rebuild and to rebuild those tissues it takes energy, and what is energy to our body? calories. So weight lifitng burns calories over the whole span of your body rebuilding those muscle tissues. And when you burn calories you lose fat. Remember burn more calories then consuming in a day to lose fat. When adding muscle and trying to lose fat at the same time make sure you get a good intake of protein, do daily cardio, and dont eat fat. good luck.