Hi there,
I switched to essentials broadband plus stream last week, £20 per month package.
I managed to add essentials entertainment (£8), Sky Sports and Cinema collection (£28.75), and BT Sport (£10) using my remote control. Go to the apps section on your stream box and you should see an upgrade app there then just select the tv upgrade options you would like. The prices quoted above end on 31 March I believe although are valid for 18 months from your upgrade date.
Hope this helps,
Paul