starting with automation+paginated reports

Hello,

I am making my first steps in report building and automation world.

I have this project of building a report which originally is made with excel, and contains 4 sheets - 

3 sheets of data that are manually updated with latest data when the report building starts,

and 1 sheet which is the final report and contains calculations like summaries of columns from the other sheets.

In order to build this automatic report, i am using these tools:

• sharepoint folder
• Power Automate
• Power BI Desktop and Service
• Power BI report builder.

I have a working Power Automate flow that starts with recieving an Email with the new data,

and ends with sending an email that contains an updated paginated report,

but i would like to focus on the report building proccess - 

Whenever an Email arrives with the new data (in excel form), it updates the dataset (located in the service) containing the oudated data.

Now i have an updated PBI report in the service which contains the 3 updated queries (fed by the latest data)

From this point i am a bit stuck and i dont understand where do i build the final report, and where do i create the columns with the calculations (mostly summaries) - in Power Query\Power Bi,

or maybe in Power BI report builder?

If anyone has any tutorial to share with me about these proccesses i would be grateful.

Thank you.