Hi Dickens
You will need to create an CSV (which is a file created in excel) with the boxes 1-9 and the applicable rows,for amount,total amount etc and then it will just need to be saved to the pc and then as long as you have contacted HMRC to authorise MTD you will have a submit with spreadsheet on the submit return drop down. Which will then do the submission through the bridging tool.
We have included a link with more information of the steps to follow here
Any other questions let us know
Emma