Click on the magnifying glass in the top right corner of your display.
The search window will open, it looks like this:
Enter the terms you are searching for in the white space and hit enter.
Depending on what you were viewing when you clicked on the magnifying glass you will see a check box to search just that category. Selecting this check box will limit your search appropriately.
For more advanced searches you can click on “options”, which will then display:
Most of this is self explanatory.
“I’ve read” is useful for finding a post you’ve read, but can only remember a minor detail of. The inverse of “I’ve read” is “I’ve not read”, this one is in the picklist at - “Any”. (These filters only work on posts created since the migration to Discourse, the old J-L site didn’t keep statistics about user activity the way the new one does.)
Once you have defined your search, click on the blue magnifying glass icon to execute it:
The search engine will display relevant items below the search options box. You can change the search definition and search again by clicking on the magnifying glass.