There are multiple ways to search for files or directories. In all cases, the search will be performed on file and directory names. Searching by file size, modification date and other properties is only partially possible in the preinstalled graphical tools. Such searches are easier to do on the command line.
Using GNOME Files
In GNOME Files, navigate to the directory from which you want to start the search. Then start typing the search term. To search for objects with a certain modification date or file type, click the arrow-down icon of the search box and modify the properties.
Using the Activities Overview
Open the Activities Overview by pressing Meta. Then start typing the search term. The search will be performed within your home directory.