How can I connect my computer to my television and do I need internet?

I have a flat-screen schaublorenz television and a somewhat older desktop. I would transfer the image from the laptop to the television. I connected the laptop and the TV with an HDMI cable. However, the television always indicates that there's no signal. I've tried everything and still it doesn't work. Also, I don't have internet on the television. What should I do?:/

Did you also select the correct input in the menu?

The television is also just a monitor. It works a little differently, but that's basically how it is.
Connecting the cable should work.
Right-click on the empty space on the desktop and go to Display Settings.
And recognize there. Two screens must be displayed.
Usually this happens by itself

Try with [WIN] + [P], that should be able to switch the monitor. Or look in the settings of your computer to see if it recognizes the 2nd screen at all.

Yes. Do I have. It worked before and suddenly it didn't and I really don't know why.

I'm supposed to install the driver again.