How do you expand mini pets shelter?

To expand your Mini Pet Shelter, you will need to collect resources and use them to upgrade your shelter. You can collect resources by completing tasks, such as feeding and taking care of your pets, or by finding them in the environment. Once you have collected enough resources, you can use them to upgrade your shelter by clicking on the "Upgrade" button in the shelter menu. This will increase the size of your shelter and allow you to house more pets.