@Anonymous User @schnapps That model is an old 42" HD ready set with a DVB-T tuner. It can play films from a USB stick and that's it.
You can watch NOW TV on that set using numerous external devices, such as a NOW TV Box, Chromecast, Apple TV etc connected to a HDMI port.
Hi @Anonymous User do you have a Chromecast? You can use that plus a mobile to watch Now if you have one.
If it's not a smart TV with the inbuilt NowTV app, then if you have a spare HDMI port on the TV, then see the list of supported NowTV devices on the link page below.
My recommendation (if you don't currently own any devices on the list) would be a NowTV black box with the free voucher pass which you can buy from places like Amazon, Argos etc for about £15 to £20.
Amazon link for NowTV black boxes with vouchers (see below).