To start the process of creating a monitoring portfolio in Salesforce Business Intelligence you have to click on the Business Intelligence tab within the application:

Within that tab in the top right hand corner is the Monitoring button which will take you to the Monitoring page which will display any notifications for the monitoring portfolios:

The monitoring page shows any notifications for monitoring portfolios that you create if there have been any changes to the businesses being monitored. Within this page there are two buttons in the top right hand corner, one fore going back to the previous page and the other called 'Portfolios'. If you click the Portfolios button this will take you to a page that contains all the Monitoring Portfolios that you create. 

The Portfolio page will contain all of the portfolios that you will create and there is a Create Portfolio button in the top right hand corner.

The Create Portfolio button will take you to a page where you are able to create a portfolio and which will contain the companies that you would like to monitor and the rules that will . Shown in the example below:

Note: If you leave the Min and Max value blank it will notify you of any changes made.

Once the configuration is saved it will take you to the 'Company Information' page where you can add any companies that you have added in the accounts section of the Salesforce application previously.

Once the company/companies are added to the portfolio it will take you back to the Portfolio page and will display a new button called Manage Companies and the number of companies within the portfolio in brackets. As shown Below:

Then you click Save Configuration and the portfolio is added to the Salesforce application.

To manage or edit the portfolio you just click on the edit button next to the portfolio you would like to change and it will take you back to the Edit Portfolio page.