Prerequisite: You need to be a Jira administrator to do the initial setup of the app.
Search for Smart Connect for Jira app
To get started please go to Jira Settings → Apps → Find new apps
Search for Microsoft Teams or for yasoon and click on the app.
Start the trial
Now you can click on Try it free and start your trial for 30 days.
Later, you have confirm your trial on the next screen with Start trial.
You can find more information about the permissions here.