Yes, you should use a HBoxContainer to line up your different elements when you want to display them horizontally. It prevents these things from happening when you try to display your elements with different screen sizes and resolution etc. Godot has very good UI capabilities, and I have heard experienced users enjoy working with them a lot more than other game engines, but it is a whole can of worms and something to be learned. I'm not that good at it myself yet (as evident in my own entry).
It's ok, it's not the end of the world, and after all the main purpose of these game jams is to learn these things so you become better in the future.