We offer a set of concrete guidelines to facilitate and standardize the process and contents of pre-registrations, see van 't Veer & Giner-Sorolla, 2016 (JESP).
You can find 'Step by step instructions to use the osf for pre-registration V2' under files. You'll also find the pre-registration template there. This Word file includes all the elements you will be asked to fill out when you register you project (Registrations > New registration > ‘Pre-Registration in Social Psychology (van 't Veer & Giner-Sorolla, 2016): Pre-Registration’ > Create draft).