Cant get the next page tag to work withing my theme

Hi everyone I have been having a lot of trouble with this for the last month and haven’t been able to work it out.

Basically I want to split my pages and posts that are too long into several for a better user experience.

When I use the <!–nextpage–> tag it works for the first page (i.e it cuts it off where I want it to but when I click on page 2 it then gives me the entire post back as if its redirecting me back to page 1 even though it says /2/ in the URL.

I recently added a plug in (but have deactivated it now) called WP-PageNavi so that I could add a little style to the navigation between pages.

I added the code for this plugin into my Single Post (single.php) and the plugin worked but I didn’t know I would still have to use the <!–nextpage–> tag.

Anyway the plugin worked and my navigation looked more stylish but I was still having the same problem. So I think that it’s definitely got something to do with the <!–nextpage–> tag not working properly.

I was wondering it anyone knew how to solve this problem and once I get the tag working I would like to use the WP-PageNavi plugin to add a little style.

I’m not great with code or where to put it so could you please walk me through what to do and which template to insert code if that’s what has to be done.

Thanks for any help you can give me.