openlog Artemis: setting IMU sampling rate

I am new to OpenLog Artemis but have been using logomatic and arduino unos. How do I set the IMU sampling rate to 250 Hz per IMU datasheet? Using Arduino IDE and serial monitor I select “configure terminal” → “setting IMU log rate” from the Artemis monitor program but I can only set it to 108 Hz.

I’ve gone through the “Hookup Guide”. I didn’t find that very useful. Is there a user manual or tutorials I can download?

I don’t understand the code I’m seeing posted on the forums. OpenLog comes pre-loaded, all I need to do is enable/disable the sensors I want to use and set sample rates - right?