Here it is with screenshots:
- Download the ICS file and save it (do not open it) - remember to which folder you save it. This is how the options appear in the Microsoft Edge browser (other browsers will look different, but the idea is the same: Save the file, do not open it).
2. Open that folder, and right-click on the ICS file.
https://learn-attachment.microsoft.com/api/attachments/f60cc51f-2eb0-4d71-b552-0d38bf3fa78f?platform=QnA&fud_access=wJJIheezUklbAN2ppeDns8cDNpYs3nCYjgitr%2BfFBh2dqlqMuW7np3F6Utp%2FKMltnRRYFtVjOMO5tpbpW9UyRAwvLeec5emAPixgq9ta07Dgnp2aq5eJbnfd%2FU3qhn5468d%2FAcsoZ8qAcl1BsgcI7Y0G0g9hxpO7IbEMVZcrPpyiP03IM4MEpwNf6IvnX3mgb31pTWddAtnYGrjkYI%2FpDTGmWJrV5lNfZq39LM%2BGCf1C5EbS%2FeWk4DBL9KdJUlgD237WXTOX2K1irCQXM0K7IYz4jChp%2BCwXiHqjYdxV3M4VxNkGVsoH2MfVU04i7gZ%2FRm5Tq2bYgrLLXAZFznKAOqp6mu5zp7YdgYENreMu%2FJP%2FOIPCxdQ4NvMBsv0OmBGfLKkleom8nVJR8kEmqFHll4ofnnaJmyp3%2FbVqg2mJlqw%3D
3. Click on "Open with" and then scroll down to and select (click on): Outlook (new)
4. Select which calendar to add the event to (you might have only one calendar, but you still need to select it). First click on the drop-down arrow, you will then see your account email address with Calendar below that—click on Calendar.
5. After you select your calendar, click Import.

There are other methods to accomplish this task, but this is the simplest (easiest) for me.