Wow, you're lucky! Kudos to your gym for acquiring one of these. I wish my gym had one too.
What is that?
It's commonly referred to as a "bamboo bar" because of its resemblence. It's actually plastic, as I'm sure you've surmised if you've tried it out.
Eric Spoto (one of the best bench pressers in the world) is a strong advocate for incorporating the bamboo bar bench press into your routine, because of the instability it causes, which in turn forces you to activate a lot of the balance muscles that usually don't get a lot of focus.
How do I use it?
He advocates using quite low weights, and going for 3-5 sets of 10-15 reps. There's really no point trying to measure your 1-rep max on such an auxilliary exercise. This is for volume, and to train those hard-to-engage muscles.
In terms of "how do I even?", you use it like you do with a regular bench press. Same setup routine, same prep, same execution. It's just more unstable.
Another benefit is that if your bench technique isn't very good, it will let you know very quickly that you have some flaws in your setup. And more importantly, working on this variation will help resolve those issues.
I highly recommend watching this video, where Eric Spoto himself takes the time to instruct and demonstrate this movement. https://www.youtube.com/watch?v=5AHCpJecV2U