You can simply pan the map by swiping or you can search points of interest or trails using the magnifying glass search icon.
Navigate to the area you want to download.Deselect all other maps sources for optimum download speed and size. While viewing the map in the iOS or Android Gaia GPS app, click the Layers button at the upper right.
However, downloading maps for offline use requires a Premium Membership. Make sure you have a Premium Membership to Gaia GPS to download maps.