The bookmark file is a .htm or .html page on your computer? When you edit your home page address on the Options page, the new address should be saved as soon as you tab out of or click away from that field. There isn't a save button. Another way to set the home page is to first load the document in a tab, then drag the little "i-in-a-circle" from the left end of the address bar and drop it on the Home icon on the toolbar. Firefox should ask you for confirmation to save the current page as your home page. To test whether it worked, you can press Ctrl+n to launch a new window, and that page should display. If Firefox won't let you change your home page AT ALL, there may be a different problem, such as an add-on interfering, or some malware on the system. If Firefox lets you change your home page, BUT after you exit out and start Firefox again it has forgotten, there are a number of possible reasons for that. This article covers many of them: [[How to fix preferences that won't save]].