Yamaha QY 300 Owner's Manual page 39

Press the [F6] key ("Exit") to return to the SONG mode when done.
Select the Track to Record
Move the cursor to the track area of the display, and then shift the cursor
sideways to select the track you want to record: 1 ... 16. Move the cursor
vertically to move to other areas of the screen. The selected track will remain
highlighted.
Engage the Record Ready Mode
Press the key to engage the record ready mode. The red LED above the
key will light.
Select the Step Record-Mode
Press the [F5] function key ("STEP") to select the step record mode.
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