This document provides guidance on using the geoMapTool application for field validation purposes. It describes the objective of geoMapTool which is to allow users to add attribute information to OpenStreetMap data both online and offline. It provides details on the application's development history including beta testing in Manila and field validation in Fiji. It outlines the functions and features of geoMapTool in both online and offline modes for editing OpenStreetMap data. Finally, it provides guidance for field mappers on mapping protocols, attributes to collect for different map features, and good practices for uploading and verifying edited data.