Add Bookable product to cart in woocommerce

I have used Woocommerce bookings plugin and added my plugin which enables users to select more than 1 slot at a time. When i click on “Book Now” button,if the user has selected 5 slots, only the last slot gets added to the cart. I want to add the remaining 4 slots to the cart. I cannot use only product_id as a parameter, as it will not accept further slots in the cart. I want to add all 4 slots along with the 5th slot that woocommerce adds.