Steaming & a Samsung Smart TV

I am thinking of switching to DirectTv Streaming from Xfinity (getting too expensive) I was wondering if anyone that has a Samsung TV let me know if when you turn the TV on, does it automatically start the DirectTv Streaming or do you have to click on the app first to go into the programing? 

My almost 80 year old mom lives with me and I need something that is easy for her to navigate. It would be great if she could just turn the tv on and it automatically starts playing the streaming service, like it does for Xfinity. 

I do have the tv set to automatically play the last service that was playing when the tv is shut down, but that doesn't really seem to work, my tv has turned off when watching the Pluto app but when I turn it on, it automatically goes to Xfinity. 

I'm open to suggestions, Thanks