Welcome to the forum. Unfortunately only the movie pass can be watched on YouView boxes , not entertainment, kids or sports.
Have a look at the following list of supported devices as you might find you already have something that you can watch entertainment on. If not, a NOW TV box is probably your cheapest option.
If you do have another compatible device such as a games console, Roku, Chromecast etc that you want to set up, you can find more details here
I bought the Cinema and Entertainment pack yesterday. Trying to watch it through my BT YouView but only lets me watch Cinema. Only bought it so I could watch Modern Family and bought to movies to keep the missus happy. Seem to have come off worse on this
You are about a year too early, BT and Sky/NOW TV announced a deal today: BT and Sky agree to show their TV channels on each other’s platforms
"BT today announced a multi-year agency deal for BT to market and sell Sky’s NOW TV service to BT TV customers. NOW TV offers Sky’s most popular content, including Sky Sports, Sky Cinema and the Sky Atlantic channel.
Sky will make the full NOW TV service available on BT TV’s set top box and BT will be able to sell subscriptions to NOW TV’s great passes directly to BT customers.
BT customers will be able to watch Sky content as part of their BT TV subscription.
At the same time, BT has agreed to wholesale its BT Sport channels to Sky, allowing Sky to sell these channels directly to Sky satellite customers. The BT Sport channels include exclusively live UEFA Champions League and Premier League football. This will mean that satellite customers will be able to buy BT Sport from Sky as well as from BT.
The agreement brings to a successful conclusion negotiations that have been on and off for a number of years.
The agreement demonstrates the importance that BT places on sport, and enables BT Sport to reach a new audience.
Currently, BT TV customers can only buy Sky Sports Main Event as a bolt-on to their TV service for £27.50 per month, and are not able to choose from the full range of Sky Sports channels. As a result of this agreement, BT TV customers will be able to take all eleven Sky Sports channels, as well as a NOW TV Entertainment pass offering great channels including Sky Living, Sky One and Sky Atlantic, which also offers box sets including Game of Thrones, Big Little Lies and Billions. BT customers will be able to buy all of this in competitively priced bundles with BT TV.
It's expected that these new services will be available to customers from early 2019."