It's a good idea to have English present at home (or in the car!) so it becomes a language that kids simply get used to hearing and not just confined to the classroom or playgroup. It really doesn't matter if they don't understand everything, it's important that they enjoy listening and they'll slowly pick up the words and sayings. I personally prefer using listening skills rather than the visual screens. But putting their favorite cartoon/film on in English is useful too.
This is a good BBC episode of Playtime all about music using songs, body movements and a story. (The story is a bit long so you could skip it for now) https://www.bbc.co.uk/sounds/play/p065467q