If you want to have a sticky menu like the one in One page, you can try to add this custom class in block "Menu" of the layout you use for Blog page:
But the style of Blog is different from One page, so the menu cannot look exactly the same.
You can see the attached image.
Ok. I see the problem.
Our developer is updating MeetUp template, and he will include an option for fixed menu in the next version.
Could you please wait for us? We will have announcement when MeetUp v1.1 is released.