Download the softphone installer from the official website via this link. Install it by following the installer instructions.
In the interface, create a new account.
Fill in the server address (IP address of your MikoPBX), login (employee's internal extension number), and password (SIP password from the employee settings).
Successful authorization is indicated by a green flag next to the current account. Additionally, the status for this internal number on the PBX should show as Connected.