MacBook Pro refuses to open ”OpenOffice”. What should I do?

[Thjelvar]

I am trying to install OpenOffice on miRn MacBook Pro (with OS X Yosemite 10.10.5 version) but the computer refuses to open the program. A message says:

"OpenOffice can not be opened because it is from an unidentified developer.
Your security settings only allow installation of applications from the Mac App Store and identified developers. "

What can I do for the program to work on my computer?

Regards
Jan C

[RoryOF]

See this posting
viewtopic.php?f=17&t=87668&p=411409