Import Firefox Bookmarks

Step 1: Export from Firefox

Open Firefox
Click the menu button (three horizontal lines) in the top-right
Click Bookmarks, then Manage bookmarks at the bottom
In the Library window, click Import and Backup
Select Export Bookmarks to HTML...
Choose a location and click Save

Step 2: Import to Arcmark

Open Arcmark
Go to Settings (gear icon)
Scroll to the Import & Export section
Click Import from Chrome, Safari, Firefox
Select the HTML file you exported from Firefox

Note: Your folder structure will be preserved during import. A new workspace called "Imported Bookmarks" will be created with all your imported bookmarks and folders.