1) Gorilla Expense Great Plains 2010/2013 Setup.Docx -> This is a quick start document provided by Gorilla Expense that will help with installing GP web service. It briefly describes all the steps involved in installing GP Web services (If you would like to see detailed steps, they are provided in the WSInstallAdminGuide.pdf) This document also has instructions on how to configure GP Web Services after installation, so that the web services are ready to receive data from Gorilla Expense

2) WSInstallAdminGuide.pdf -> This is a Microsoft document that is available in the GP installation folder. It has detailed instructions on installing GP web service. 

PS - If you are sending data from Gorilla Expense to GP Project Accounting or GP with MEM, please install eConnect instead of GP Web Service. eConnect needs to be installed on the GP server and on client machine where Gorilla Expense Integration App will be installed (typically AP Managers machine)