Below is a link to the M5 Armband User Guide
https://trainwithmorpheus.com/m5-user-guide/
Below is a link to the M3 Chest Strap User Guide
https://trainwithmorpheus.com/m3-user-guide/
If you cannot find what you are looking for in these these user guides, please reference the various FAQs at the links below.
M5: M5 Armband FAQ
M5: M5 Maintenance and Troubleshooting
M3: M3 Chest Strap Troubleshooting