The search/filter bar will look in every column for whatever you type. You can type dates (e.g. "Sep 20" or "Dec 15"), look for free events only (e.g. "Free"), age restrictions (e.g. "18+" or "all ages"), specific promoters (e.g. "Insomniac" or "Surface Tension").
When you use multiple search terms in a row without quotes, the results will be any rows that match any one of the terms. For example if you search
house free techno (without quotes)
Any row that has the word house OR free OR techno will appear.
When you use multiple search terms in a row with quotes, the results will be any rows that have ALL the terms. For example if you search
"house" "free" "techno" (with quotes)
Only rows that have the words house AND free AND techno will appear. You must use exact terms when using these quotations. For example "trance" "free" will not show parties that only have psytrance and are free, but "psytrance" "free" will.
You can also use the "-" character to do a negative search. For example if you search
house -free -techno (without quotes)
Only rows that have the word house but NOT the word free and NOT the word techno will appear.
typing "tech house" in the field will just pull up events with the exact string "tech house"
Hope this helps! Also, you can always Ctrl-F too :)