The packages which the agents upload usually include a few alternatives for accommodations and activities for you to choose from. Alternatives are selected by clicking on either "Select Room" for accommodations, where you can change your rooms or accommodations, or by clicking on "Customize activity", to change the activity for the day. This way, you can easily customize the packages yourself.
If you are still not satisfied, the local agents are happy to help you design your very own trip based on your wishes. Just click on the "contact" button next to the trip and write a message to the responsible agent. They will get back to you as soon as possible.