Can't stream on TV because get "no signal" when I power up the tv.

"No signal" is just information.  It doesn't necessarily mean anything is wrong.

For example, when I see that, it's usually because a device like a Blue Ray player or a Roku needs to be turned on/woken up, or I don't have the TV on the right input.

In the simplest case, you might want to press the home key on your Roku remote, or you can turn off the auto power savings: System -> Power -> Auto power savings

Hey there!

Welcome to the Roku Community, glad to have you here, Ksenia!

In addition to this, we would also recommend checking this support article: What to do if you cannot see the picture from your Roku® streaming player on your TV.

Please let us know if you need help with the process!

Best,
The Roku Community Team