Hello, where can I change this: I chose Single Choice options, but I want them to appear one after the other on the actual form. Not underneath each other.

You want to display the options of your single-choice questions one after the other means you want to show options horizontally instead of vertically, for this you need to enable the "Spread to column" checkbox in the General tab of the element. Additionally, select the number of options you want to display in one line.

Please refer to the screenshot below for instructions on enabling the "Spread to Column" checkbox.

If you would like to present your single-choice questions one at a time, you need to add "Page Break" elements below each question in your form. This way, each question will be displayed on a separate page.