How can I put up temporary room partitions?

Ali: a fold screen could work well.

You can use furniture to define the space, even rugs. If you need it separated, I like using back to back book cases so they will be anchored against each other.

Ikea has a system of panels that ride in a track attached to the cieling. Think hospital bed curtain but where the curtain panels are semi ridgid and weighted at the bottom. They can close off an area yet can also slide back to open the area. You choose your tracks by how you want the panels to stack when open. And choose your panels by design style. You can also hang you own fabric or curtains with hooks. If the length is not too long you can also hang curtains on a wire system.

Here's what some other Hometalkers have done:

https://www.hometalk.com/diy/decorate/10-creative-and-beautiful-diy-room-divider-ideas-41279271

Here's some more pictures for inspiration:

https://www.pinterest.ca/ursulahippie/temporary-room-dividers/

Get tall bookcases, face one to one side and the next one the other way, then back again. Put baskets on some of the shelves. That gives storage to both sides of the room. Be sure to anchor it to the ceiling, floor and each other for safety.

Home and Garden DIY Ideas | Hometalk

Home and Garden DIY Ideas | Hometalk

Amazon actually carries room dividing tension rods up to 20’ wide room!

You can use your cabinets and other furniture.