.java, JOptionPane, IF-else conditions [on hold]

Rick Hammer is a carpenter who wants you to write a program to generate a price estimate for customer interested in purchasing a custom desk. The estimated price is based on: desk length and width in inches, type of wood, and number of drawers. The estimated price is computed as follows:

The minimum charge for a desk is $200. If the surface area (length times width) is over 750 square inches, add $100. If the wood chosen is cherry, add $225; for oak, add $150. No charge is added for pine. For every drawer in the desk, there is an additional $50 charge.

Here is the question I have. I used JOptionPane, and it worked for the inputs. But as soon as I use If-Else conditions I get compiler errors. Any help would be great.