@tricky Thank you for your reply. I actually created a few test files for testing on Keepit and Keeweb, but they still do not work.
@CiberSheep Unfortunately, after I use File Manager to select the keepass file which I want to open, the file is not listed below in the app (see screenshot). What am I missing? Would you mind please posting a video of you selecting a keepass file, selecting a key file, then opening that keepass file so that I can see what the process is supposed to look like? Thank you