I wish to install files on /mnt/sdcard/MyDir by instalation, so i don't need to have these files in my DirAssets directory. But i don't know, how. Thank you , comunity, for a litle help.
As @mangojack already stated there is a solution how to copy files from assets to somewhere else.
BUT you NEED to have them in your Assets. That´s the way you redistribute your app.
You can put them on a webserver and download the files and save them to sdcard. In this case you dont need them in assets.