What's the problem? There are a number of methods one can use to access an online service (Spotify) with a device (TV)
Method one, if supported, is to download the service's app to the TV and then follow the directions to authorize it and sign in with your user name and password for the service.
Method two would be to use a web browser on the TV to navigate to the Spotify page and sign in.
Method three would be to add another device to the TV that supports the Spotify app. If you have a streaming stick (Roku, Amazon FireTV) you can download the Spotify app to it. Blu-ray players and cable boxes are two other devices that you may be able to download the Spotify app to or have a browser.
Good luck.
