To change the number of columns, select the column block to open the settings panel. You can show up to 6 columns. If the theme has support for wide align, you can also set the alignments to wide and full width.

Below is a column block with six columns, and no alignment:

Next is a 3 column block, with a wide alignment:

And here is a two column block with full width, and a longer text. Make sure that the text wraps correctly.

We can also add blocks inside columns:

But wait there is more! We also have a block called Media & Text, which is a two column block that helps you display media and text content next to each other, without having to first setup a column block: