How do you get all 4 columns to show next to eachother. right now it shows 3 then the fourth is below it.

Welcome to PickPlugins.

Sorry for my late response. You can use the percentage value under the Grid item width.
First, go to the Edit mode of your Grid.
Screenshot: https://i.imgur.com/TixSa4A.png

Then under the Grid settings, set a percentage value instead of a number.
Screenshot: https://i.imgur.com/hRJOFN9.png

Or, you can easily create a grid with our post grid block.
Go to a new page, and choose our post grid block from the block inserter.
Screenshot:
https://i.imgur.com/1ccNOIB.png
https://i.imgur.com/SscprRa.png

Let us know if it helps.
Regards.