Lost home page button

I have just moved from an old laptop to a newer one - a Lenovo Thinkpad. I have installed Linux Mint and successfully transferred my files and Thunderbird. I also synchronized Firefox and all my add-ons, bookmarks and history came across perfectly. While setting up the toolbar from the customise screen I dragged the home page button onto the toolbar and it just disappeared. The home page is set up in settings. It appears the first time I open a window. I would like to be able to go back to my home page at will, how can I re-instate the home page button?