Title tags ? Apparently my blog doesn't have them ?

Hi I’m not great with computer stuff but recently I was told my blog (The LifeStyle Compound) doesn’t have title tags ? I’ve googled and googled but can’t find out a proper explanation of this.

I tried the one where you enter title and description in the general settings but that made it appear below my logo and tagline- the same thing but smaller ? Which completely ruins the look of the header.

I assume I put it in the header php file from what I can understand ? But what and where exactly do I put it ?

Thanks in advance.