Soundbar Newbie Basic Questions

Hello everyone, I have a question about a soundbar I've purchased.

In the interest of full disclosure I should say I know nothing about any of this stuff. I've just bought what is the first television I've owned in years because we've moved house and I saw a soundbar in the supermarket, I'd heard people mention soundbars before... so I just bought it...

Now I've opened it up and connected it to the television and power. It works, but I've got a few questions if anyone can help me...?

  1. It came with a power cable and Aux cable only. Is that normal?

  2. The only Aux port on my television is the headphone jack. So I plug the soundbar in and the television speakers stop working. The soundbar does give off plenty of sound... but I feel like I've just traded in my television speakers for the soundbar...

  3. There is a HDMI port on the soundbar, would that work if I bought a HDMI cable and connected to the television? Can the television and soundbar speakers work on unison?

  4. Anything else I should know?

Sorry for the basic questions!