Sorry for answering in English, but I don't know Portuguese. I hope that some of these can happen to be useful. If you still have the problem, feel free to tell us and describe it better, maybe we will work something out
Are you sure that you are opening the files after downloading them?
If you choose to open them as a download option, then instead maybe try to download them first, then run them manually?
What should happen is: the songs are being added to the game, while at the same time, downloaded beatmap (song) files should disappear. If the game is closed, it will open automatically, so the songs can be added.
If downloaded songs did disappeared or it looked like the song was added, but you can't find them, then try to use F5 key on the song selection screen or try restarting the game.
So, I would advise:
Make sure you are logged in your browser (well, you can't download songs, if you don't), then
make sure that you are opening the files. Try to do this
with your game closed: if the song files are correctly opened and game tries to add them, it will open automatically to do so.
If it opens, but you can't find the songs and there isn't any in-game pop-up error message, try to use F5. If you still don't see these new songs, make sure that they are not filtered out. There's also an option in preferences to hide songs that are too easy or too hard, but if you didn't touched it, it should show all, by default:
https://puu.sh/wKAKY/028d1b1e55.jpg .
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About this filtering and sorting options, maybe it's not really related to your current issue, but if at some point all the songs were to "disappear" for you, which sometimes happen for new players, make sure that you are not searching for something: just writing anything on the song selection screen will make you search for it, but if the phrase can't be found, this will result in no songs being shown:
https://puu.sh/wKA9Y/12d8e46c26.jpgFiltering and sorting options can sometimes make your song, especially if you choose "Collections", which is empty by default. If shows some results for me in the screenshot below, but without any collections it would show no results, like in previous screenshot
https://puu.sh/wKAaA/c510ab6c06.jpg
