You will go to the "Income" section of your return and scroll down to self-employment- click- continue- until you get to the page where it says- (Your name)did you have any other expenses?

How much did you pay for Other Expenses?
Enter the amount you paid for other expenses, such as disability-related modifications, leasing equipment other than your automobile, private health service plans, and allowable reserves. (This is where you will enter the rental fees) 

This also includes convention expenses. If the convention fees include the cost of food, beverages, or entertainment, and these do not appear separately on your bill, you must subtract $50 per day from the total convention fee. You can deduct the daily $50 amount as a meal and entertainment expense, to which the 50% limit applies.