Schedule a meeting in a different time zone

I'm in London and the person I wish to set-up meeting with is in Chicago, USA. I do not understand how to fill-out the schedule. Chicago is not in drop-down menu.

I am a complete beginner and not computer savvy. I need precise understandable instruction.

Can any one tell me simply how to fill in the Zoom schedule. I downloaded Zoom in June 2023.

Thank you.