Could you please describe your problem with more details?

Are you using a different computer are did you lose the bookmarks on your current computer?

Are there any compressed .jsonlz4 backups present if you check this in the Library?

• Bookmarks -> Show All Bookmarks -> Import & Backup
• https://support.mozilla.org/en-US/kb/Lost+Bookmarks

Do you have an "Old Firefox Data" folder on the desktop in case the Refresh feature in Firefox has been used and a new profile has been created?

• https://support.mozilla.org/en-US/kb/reset-firefox-easily-fix-most-problems

Type about:support<enter> in the address bar.

Under the page logo on the left side, you will see Application Basics. Under this find Profile Folder. To its right press the button Show Folder. This will open your file browser to the current Firefox profile. Now Close Firefox.

This is your current profile. Copy the folder As Is to a folder on a thumb drive. Then Copy the folder to the new system.