To apply overhead and profit to a claim, head into the claim in question and go to the Total Page of the estimate. The first button along the top of the Total Page will be the O&P button. When you click the button, you will be presented with a pop up menu where you can define the overhead and profit for this estimate.
You can apply the O&P as a percentage of the estimate, or as a fixed amount. If you want to manually enter a fixed O&P dollar amount, check the Fixed Overhead and Profit checkbox. This will require you to calculate the amount of overhead and profit that should be applied to the estimate.