BMR's timezone is whatever timezone you set it to show. so you have to wait 23 hours from the last time you posted. so if you posted 4 pm yesterday. you can post when it's 3pm today. the easiest is to have bmr show the same timezone as the one you're currently in. that way you can just keep track on the clock on your computer of phone.
if you somehow let it show a different timezone than the one you currently live in, it will be extremely hard to know when to post, as you'd have to calculate the right time.
you can choose your timezone in preferences. just click on your username at the top and you'll find it almost at the bottom of the pop-up menu!