What is the alternative method for accessing the Yealink cordless phone by logging into the user's PC/local network, and what steps are involved?

Confirm the square base is plugged in and has all 3 lights green 
Press OK, Status, Base: Confirm IP address 
Take the IP address and from local PC go to https://IPAddress or just enter the IP address into the search bar 
Just like Peplink you will see a safety warning. Click on Advanced, then Proceed