Using the search function
You can search for decisions, to-dos, minutes, or documents by clicking on the search symbol at the top, then selecting the desired item type:

When you search through documents, results are returned if a match is found in the document title as well as in the body.
Click on "Filters" in the top-right corner to add further filters, by board, tag, decision timeframe, or meeting date (under "individual" you can select a custom timeframe):

Scroll to the bottom to apply the filters and refresh the search results or to clear the applied filters:
