Use the down keys to cycle through different modes for the simulator. You can click each LED to illuminate it. Use the LEDs mode to view the LEDs list. This simulator does not work with the display text block, and will only display LEDs through using the LEDs list. Click on the LEDs to illuminate them and export the list to save your image as a text file.
This video tutorial walks you through Micro:bit code blocks. https://scratch.mit.edu/discuss/youtube/d9c7mDL9I5o
