Macro for Excel - 'When and Printf' style

Hi all!

I'm using Real Time Data to extract data from one platform to Excel. I would like to plot a chart on a minute basis using Macros, but have no idea how to code it.
The coding should be easy for someone with VBA knowlodge.

What I need is something like: "When is 9:30, print the value from cell A1 on cell B1"

I intent to create a huge data sheet minute by minute using that Macro and then plot a chart the usual way.