Just type what you're looking for, 3 characters minimum
You can quote text to search for an exact match ("search")
You can search before or after a date (before:YYYY-MM-DD, after:YYYY-MM)
It is also possible to search for a specific date (at:YYYY)
You can filter by tags using tag:name
To search for multiple tags (inclusive), either do tag:name1,name2 or tag:name1 tag:name2
If a tag has spaces, use quotes around it