If you know where the file is, you can browse through the folders structure and find it manually.
Along the way, there are many ways to make the browsing experience easier, especially if there are many files and folders to navigate through.
NOTES:
The filtering steps are optional, though they make the process simpler the more files and folders there are to navigate.
REFERENCES:
To help you understand these concepts better, view the how-to videos on:
File Open Video