step vs. infusion massing

So I'm new to the world of home brewing and have two quick questions. The first being, if a recipe calls for a step mash, would it make a huge difference if I do an infusion mash instead?

Also, if I'm going to pitch dry yeast, other than cooling the wort, is there anything else I need to do to the yeast before said pitch?

Thanks a lot, any information would be a great help.

 

What to do with dry yeast is a bit of a controversy. Some just pour the dry yeast on top of the wort. Let it sit for 5 minutes and then stirr vigorously to mix in the yeast and aerate the beer. Some folks say to hydrate the yeast before pitching. Some recommend hydrating in wort just like a starter for liquid yeast although for a much shorter time. Personally I hydrate my yeast for 20 minutes in water before pitching and it has worked well for the 18 or 19 batches I've done that way.

 

rehydrate the yeast in boiled and cooled (85 degree F) water. Let it sit for 15 mins, but do not stir. Then swirl just before pitching to suspend the yeast in the water.

I'm not going to answer the step mash question because I'm just starting out with that myself and don't want a noob giving another noob advice on that.