Welcome!
https://dokuwiki.librecad.org/doku.php/usage:faq#why_does_the_dwg_import_failGood to skim at least the FAQ after installing LibreCAD, links to howto's and other docs are at the top of the main page.
Check also, you are not in the draft mode, that has caused quite a lot confusion also.
Your English was decent enough, there are also free translators, use your search engine to find them.