A scholarly resource must be written by a scholar - an expert in the field, usually with a PhD or equivalent qualifications. Scholarly resources usually tell you about the author, so that you can assess whether s/he is a reliable expert on the information presented.
Walkmeter uses GPS to measure the distance of your walks and hikes outdoors. It functions much like a stopwatch. Open the app, tap Start, and use Lap when you want to log an interval. It maps your walk, and you can view time, speed, distance, and pace as you walk.
An in-app chat solution, such as Intercom. This will allow you to add two-way in-product messaging to any guided tours. Ideally your walkthrough tool can talk to this so you can message and tour users in tandem. A video hoster, such as Vimeo. Ideally your walkthrough tool can easily support showing videos from a Vimeo or YouTube link. You might also use a GIF creator, such as the one from Giphy (for Mac). An API manager, such as Segment, so that you can easily turn on and off various other tools.