This is a tutorial for advanced use for people who are up to editing HTML. (No CSS editing needed)
Note that this example uses the grid system from Bootstrap 4.0 (alpha) If your theme has a grid system you may want to use that instead as there may be conflicts if you include this. If your theme is BS 3.0 based do not include this CSS the HTML code is a little different col-sm-6 I think and you don’t need any custom CSS for it.
You can use the Bootstrap 4.0 grid with any theme not listed above by copying the code to the new custom CSS section of the WP Customizer.
With a grid system you can display content in a grid, in this example the are 2 columns on mobiles and 3 on desktops. (until the CSS in this site is updated actually 1 column on mobiles). The Grid system is extremely powerful and you can do many more things with it.
► Planet Earth: Amazing nature scenery.
► Planet Earth: Amazing nature scenery.
► Planet Earth: Amazing nature scenery.
► Planet Earth: Amazing nature scenery.
► Planet Earth: Amazing nature scenery.