There are so many connected devices on the market now, each with their own unique way of setting up parental controls and restrictions. Equally the functionality of these devices can be daunting with chat, game downloads, in-app purchases, third party apps on the devices (such as social media, Netflix) etc.
I always advise parents two things. Firstly look up the device on YouTube using a simple 'how to' query, e.g. 'how to restrict in-app purchases on Playstation 4'. Secondly, the wonderful people at Internet Matters have a one-stop shop for setting up devices which can be found here: