Mad mode is one of the elements of the game. Here you can collect resources. This page of the guide to Minecraft Earth is focused on this particular mode.
Map mode activates automatically when you run the game. You will see the map of your surroundings done in the style characteristic of this series.
You can see items that you can collect in your vicinity. Look for objects that can provide you with new items for your inventory. Based on their appearance, you can determine what you will find inside, e.g. a heap of soil gives various plants.
You can't collect everything you want. Pay attention to the circle on the screen - it shows your reach. You can only interact with objects within that zone. Once you collect everything within your zone, move to another place or wait for the resources to renew.