Lo-tech auidophile Boomer seeks help using new iBasso DX220 mobile digital player

I would be very grateful to anyone who could explain 3 things which the manual does not mention about this device :
1) How does one move flac files from a microSD card in the card slot to the DAP’s internal storage?
2) Where/how to find downloaded (from the web) music files using either Android or Mango OS. (A note on the desktop says the download is complete, but the “file manager” app shows nothing in “download” or “music.” Going to “settings – storage – music/audio” shows nothing. I do not find a "downloads manager" app on the desktop.)
3) Once the downloaded or SD card music files are on the DAP, how does one set them up to play?
The DX220’s manual is a nice guick-start guide, but seems intended for someone already familiar with devices like this. iBasso’s "contact us" webpage will not send: You enter your question, click send, and wait a few minutes ; then a small window flashes briefly on the screen saying "Sorry!" and the page freezes! The seller, "headphones.com," promised a response which has been delayed. A few hours of internet searching has found nothing. I would greatly appreciate whatever help anyone can provide. Thanks!