It's much easier to install the strainer before you attach the sink to the counter top. That way you can hold the strainer with needle nose pliers, or the handles of one set of channel locks, while tighten the nut (with another set of channel locks) beneath the sink. Don't be afraid to use too much plumbers putty, you can just use a regular head screw driver to time it off the strainer when you are done. And yes, it there is writing on the strainer, make sure it looks good in the sink.

For best results, after you've got the drain pipe installed, plug the drain, put some hot water in the sink and tighten the nut on the strainer just a little more. The hot water loosens the plumbers putty, so you get a tighter fit.