Can I retrieve word starter or excel starter files from LibreOffice?

As soon as I downloaded LibreOffice on my laptop, Microsoft Office (trial version) locked up my files and insists I purchase their suite. They don’t like this! Is there a way I can open and convert my files? Also will I be able to read incoming MS Word or Excel files?

I’m a new girl on the block. Thanks for your patience.

Choose Spreadsheet (Calc) or Text (Writer). Then left click File from main menu. Left click Open. Choose the file you want and open it. Once in the document, choose Save As. Then Save. You get a box with Confirm Save As: Do you want to replace it? Say yes. The next dialogue box says Confirm File Format. Choose Use .ODT Format. And then click Save again. If you want, you can then delete the Word or Excel documents.

Unfortunately, this does not answer the second question: how to read incoming MS Word files.
I get this at the top of my incoming email: This message contains an attachment whose file type is considered dangerous. The file has been deactivated.