How should I use the 検索 function?

I've been on here for 3 years now, and I still can't make heads または tails from the 検索 function! I mean, whenever I use three 検索 tags, it tells me that it cannot find the thing I'm looking for. または should I maybe just not use the 検索 function? Anyone help me. Please. I'm so desperate.

I'm gonna die if I don't know. D}: