Link to Microsoft Flow can be found under Office 365 app launcher. Here is more info about Microsoft Flow plans&pricing.
The List Web Part allows you to view tabular data on Sharepoint web page. Below are steps to add Web Part.
Step 1) Click "Edit" (you need to have required permissions to see edit option)
Step 2) Click Insert=>Web Part=>Apps, select list and then click "Add" to add webpart.
Power BI is a suite of business analytics tools to analyze data and share insights, here is more info.
Below are steps to add Sharepoint List as data source for Power BI.
Step 1) Click on Get Data=>Other=>Sharepoint List
Step 2) Copy&paste Sharepoint List URL and click "Ok"
Step 3) Select Sharepoint List and click "Load"