you have to put the people around the table to see who sits where.
here's how it ends up:
duclos the candlestick maker
andre the butcher barton the baker
charmin the grocer
here's why:
Since they all face the table and andre sits on charmin's left, then if we put andre on the left of the table, charmin has to be at the bottom on his right.
Barton sits at the grocer's right.
Duclos faces charmin.
Since we know where Charmin sits, then Duclos has to be opposite Chrmin so Duclos has to be on top.
That puts Barton on the right because there is nowhere else for him to go.
If Barton sits at the grocer's right, then Charmin must be the Grocer.
If Duclos is not the baker, then Duclos must be the Candlestick Maker.
That means that Barton must be the baker.