assuming you're doing a Shaw's Original farmhouse-style sink, there is no "left side". these sinks are finished on all four sides, so you can flip it around and put the off-set drain on whichever side suits your purposes better.

you'll need the extended flange (get one that matches your faucet) to connect to a garbage disposal. that's just because the fireclay is so thick that a normal flange doesn't extend out the bottom far enough to give the GD anything to connect to. these things aren't cheap ($125 or so) considering they're just a metal tube.

the basket is that little thingy that sits in the drain and catches crumbs or whatever. purely optional.

You can find a flange made by In Sink Erator at Home Depot for about $65. Obviously if you attach the basket you don't need the flange to connect to a garbage disposal.

The Shaw's Original label is very prominent when the drain is on one side (right, I think) so if you flip it you will see the brand.

With the label on the "back", i.e., you're looking at it when you stand at the sink, the drain is on the left.

Other than the extended flange, if you're going to do a soap dispenser, make sure you get one with an extended reach - as in the spout itself should be 4 1/2" or longer.

HTH