Here is a link to the LJ1012. There are links for manuals, drivers, support forums, etc.
LaserJet 1012 Support
As to your question, here are the brief descriptions of the 2 lights and 2 buttons...from top to bottom:
1 Attention light:
Indicates printer media input tray is empty, print cartridge door is open, print
cartridge is missing, or other errors.
2 Ready light:
Indicates that the printer is ready to print.
3 Go button and light:
To print a demo page or to continue printing while in manual feed mode,
press and release the Go
button. To print a configuration page, press and hold the Go
for 5 seconds.
4 Cancel Job button:
When the printer is processing data, press the Cancel Job
cancel the print job.
Also, see if powering down the printer and unplugging it from the wall outlet for several minutes clears the repeating of the print job.