To open a torrent file press the open or simply dobule clicking the torrent file from a web browser after opening it will start Qtransmission. The torrent file will start download and using your connection to upload to others in a so called peer to peer network. At the bottom you will see an arrow pointing downward to show how fast you are downloading. The up arrow shows how fast you are seeding or uploading the file to others.
While you download your file a progress bar with will show your download for each file once you have it entirely you have see how many people you are seeding to each person and how fast you are uploading to that person.
The button with two || circled is a pause button that can pause all downlaods and uplaods. To start donwloading and uploading again to press a button with a triangle to start uplaoding and downloading again.