Step 1

Click “Download” in the addon/map/building/texture/seed detail screen

Step 2

After finishing download, Click “Open Minecraft” , you will be transferred directly to Minecraft PE application

Step 3

In Minecraft PE:
1. Create a new map or edit existed map.
2. Scroll down and check on”Resource Packs” and “Behaviour Packs” for imported add-ons/maps/buildings/textures/seeds to activate it.