This manual is part of the following publication and has been written by the same group of authors: **Simeon Lisovski, Silke Bauer, Martins Briedis, Kiran Danjahl-Adams, Sarah Davidson, Christoph Meier, Lykke Pedersen, Julia, Karagicheva, Benjamin Merkel, Janne Ouwehand, Michael T. Hallworth, Eldar Rakhimberdiev, Michael Sumner, Caz Taylor, Simon Wotherspoon, Eli Bridge (2019 - accepted) Light-level geolocation: A user's guide. Journal of Animal Ecology.** Geolocation by light is a method of animal tracking that uses small, light-detecting data loggers (referred to as geolocators) to determine the locations of animals based on the light environment they move through. Technological and fieldwork issues aside, effective use of light level geolocation requires translation of a time series of light levels into geographical locations. Geographical locations that are derived from light-level data are subject to error which directly arises from noise in the light-level data, i.e. unpredictable shading of the light sensor due to weather or the habitat [@Lisovski2012]. Although light-level geolocation has provided a wealth of new insights into the annual movements of hundreds of bird species and other taxa, researchers struggle with the analytical steps that are needed to obtain location estimates, interpret them, present their results, and document what they have done. This manual has been written by some of the leading experts in geolocator analysis and is based on material created for several international training workshops. It offers code and experience that we have accumulated over the last decade, and we hope that this collection of analysis using different open source software tools (R packages) helps both newcomers and experienced users of light-level geolocation.