It is very hidden and compared to older OpenOffice-Versions it is currently buggy. You might consider to use an older version for this task, for example a portable LibreOffice or OpenOffice 3.*
First you need to customize a toolbar and add the tool:
Customize... > tab
Toolbars. Select the toolbar to which you will add it (likely “Drawing”) or make your own new toolbar. Click on ‘Add’. Select item “Format” in list “Category” and then item “Fontwork” in list “Commands”. Click
Add and then
Close. Move the new command up or down if needed, click
Now draw a line, a shape or what you want to use to determine the path of the text. Each drawing object has the ability to carry text. In most cases a double-click brings it into the edit mode, where you can write your text, in other cases key
F2 will work. Write your text.
When the object with its text is selected, click on the new icon “Fontwork”. This opens a window with some tools. For to get an idea how it should work, search for “Fontwork” in the headings of the help. You get two hits. Take that with heading “Fontwork Dialog (Previous Version)”. One example of the usage is in Adding text to connectors - Apache OpenOffice Wiki.