Tried it 3 or 4 times now
We don’t know your computer or what you did to it so we can’t say.
Please explain exactly how you proceeded!
What did you do to install.
What operating system do you use?
What happens when you try to start LibreOffice?
Is there an error message and which ones?
You should understand that we cannot look over your shoulder, we are blind and you have to explain it to us.