This guide will work with any Chromium based browser such as Brave.guide
Go to https://chromewebstore.google.com/category/extensions and search for Solgari and click it.
Click "Add to Chrome".
Click "Add extension".
Click the little jigsaw icon on the top right corner and choose Solgari.
A prompt will ask you to log into. Log in with your M365 credentials.
Answering or making a call for the first time will prompt you to allow Microphone access which is required for the extension to work. You are now ready to make and take calls through Solgari.