Spelling and Grammer
You can click the Tools option in the top toolbar and the top option in the dropdown menu is "Spelling and Grammer" which opens the spell check box. Or press F7.
You can also click the ABC icon in the top toolbar and open the same "Spelling and Grammer" pop-up box.
The Blue Icon is the Spell Checker option and the Red Icon is the option to make all misspelled words have a red line underneath. You can select to have open office auto-correct spelling and other things.
There are other ways to get to the options for spelling and grammer I found at least two maybe three. One is in the program options, another is in a pop-up box with various tabs, and I forget the third, but the important one is the program option which is a long list that if you click on a option opens a bunch of other options below it and then each changes what appears in the small window box. Eventually you find the font or spelling and select the language.
But First Know That You Need to Have a "Dictionary" Added as an "Extension" There is No Default Dictionary. You likely already have one though from your download.
Go to Tools in the top tool bar and at the bottom of the dropdown menu is
"Extension Manager" select that and it opens a pop-up box which should show a dictionary. Click it to activate it maybe?
If you do not have a dictionary as shown below you can download one from the open office website.
There are a few problems the dictionary can cause like not working, not spell checking, and I will do a post how to remedy that.
One quick option to fix it is make sure you have the correct "English" selected, and also make sure it is selected by "default" in the other options menu of open office. This solved it for me. I didn't have to active or redownload a dictionary and install it. I was using a different "English" dictionary and that made it so when the box popped up it said nothing to check and closed.