Separating a chord??

Please bear with me - I learned basic music theory like 9 years ago and don't really remember most of the terms for things, but I'll do my best to explain.

I'm trying to have a chord that is made up of two half notes, stems pointing down, under a quarter note, stem pointed up.

The file I imported was mostly correct, but I've been going through to tweak things. (See below) The part I highlighted in red is what I'm going for, but the part in yellow I can't "type/create" myself. How would I go about doing that?