Concatenation (join together) or Template string? Below shows examples of both. Both are correct it's your choice which you prefer.

const title = 'Practical Fly Fishing';
const author = 'J R Harpur';
const likes = 30;

//concatenation way

let result = 'The blog called ' + title + ' by ' + author + ' has ' + likes + ' likes';

console.log(result);
//result: The blog called Practical Fly Fishing by J R Harpur has 30 likes


//template string way(``)

let result2 = `The blog called ${title} by ${author} has ${likes} likes`;
console.log(result2);
//result: The blog called Practical Fly Fishing by J R Harpur has 30 likes

//creating html templates
let html = `
  <h2>${title}</h2>
  <h3>By ${author}</h3>
  <p>This blog has ${likes} likes</p>
`;

console.log(html);
//result:
//<h2>Practical Fly Fishing</h2>
//<h3>By J R Harpur</h3>
//<p>This blog has 30 likes</p>