What am I doing wrong?

I got this new working Toshiba but I haven’t used a crt since I was 10 years old so I’m failing at getting her going. Im on channel 3. Ive tried putting the connectors into the ports on the front and back and nothing (what could I be doing wrong?). It didn’t come with a remote and I see no input buttons, do I need to switch the inputs/do I need a universal remote?