If you want build add this assets to this unty project:
https://assetstore.unity.com/packages/2d/gui/icons/simple-button-set-01-153979
https://assetstore.unity.com/packages/2d/free-2d-mega-pack-177430
https://assetstore.unity.com/packages/2d/textures-materials/tiles/parallax-dusk-mountain-background-53403
https://assetstore.unity.com/packages/2d/gui/buttons-set-211824
Sorry for problem but Standard Unity Asset Store EULA...