The file lab6.ss should be largely self-explanatory. If you are implementing single bindings (a good starting point), you should follow the grammar given below for single bindings/single fields/single methods. Completing this, in addition to all the normal rules for a good laboratory (testing all your functions, extending the given test suite appropriately, etc.) is good for a B.
If you go on to multiple fields/multiple methods/multiple arguments in methods in class definitions, the lab is worth an A in your final portfolio.
(A starter file will be provided for multiple fields/etc., but is not up as of March 25th. In short, you can get an A on this laboratory without having implemented multiples in the previous laboratory.)
If this all seems brief, it is because I'm sleep deprived. Also, don't forget that the lectures from this week are available online (Monday and Wednesday).