In the help file, it says
Other options
Shows more or fewer search options. Click this label again to hide the extended search options.
I am in sheet1 and enter a find command. The data to be found is in sheet2, but the find command stops after searching sheet1. I want it to search all sheets. I do not see any “other options” selection to click on.
You did not provide the link to the help file, where you found the information but most probably it is about Find & Replace dialog, which also has an option for [x] All sheets to find in all sheets (This is not available in Find). Thus, take a look into Edit -> Find & Replace... (and assure Tools -> Options -> Libreoffice -> View -> Option: [x] Summary on Search is activated.