How can I create form with multiple fields in one row?

Also, is there a way to insert an element inside another one? For example, if I have a select boxes on the left but there is plenty of room on the right, can I put another column in?

You can shrink and move your fields around, for example:

So you can shrink them, move to the same line, new line etc.

Also, Configurable list widget will allow you to combine multiple fields in one:

Please let us know how this works for you and if you need further assistance.

Thank you!