Selenium IDE - click OK on alert box.

I am using Selenium IDE to record and run test scripts (I have to use plain
hmtl selenium scripts to link them to Qualys penetration test).
In one of scenarios web application displays an "alert" modal dialog box
with OK button.
How can I code in IDE that Selenium would click OK button and my script
would continue.
I tried everything available after searching web by the following words:
selenium ide alert click ok.

Any suggestion and example would be greatly appreciated
Regards,
Vladimir.