Did you right click on the top of the browser above the tabs and there you should see the option to turn on Toolbar. If not I'll check my FF57 later at home to see but that's where I found the option show toolbar or turn off toolbar.

Do you mean that you placed icons on the Navigation Toolbar, but you do not see them after you closed the customize window?

Open the Customize window and set what toolbars (Show/Hide Toolbars) and toolbar items to display.

• Right-click empty toolbar area -> Customize
• "3-bar" menu button -> Customize
• View -> Toolbars
  *you can tap the Alt key or press the F10 key to show the hidden Menu Bar temporarily

See also:

• https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars
• https://support.mozilla.org/en-US/kb/navigation-buttons-missing

Found it! On my computer, it was in the upper right of the screen , next to the three horizontal lined icon (open menu). The toolbar icon that mine was on looks like its pointing to the right. It looks like this: >> but a little bit bigger.

That is the overflow area. Icons normally only appear in this area when you explicitly place them there, but Firefox also can move icons to the overflow area when the Firefox window isn't wide enough. You can see this in action when you make the window smaller and wider to see what minimum wide works.

Found it. Thank you for answering everyone.