How to refresh iPad

What do you mean by “refresh”? You can restart it, force restart it, restore it as new. What do you want to do?

That is a question for SongBook Chordpro app users. Google search leads me to this link:

https://www.linkesoft.com/songbook/ios.html

You might want to read that article. Perhaps you weren't doing something right.

Dropbox Sync

If you have a Dropbox account, you can easily synchronize your song collections with SongBook. Simply enter your Dropbox account data in Settings, and copy your song files to the /SongBook directory and its subdirectories in your dropbox. Synchronization takes place either manually with the refresh button or automatically whenever you open the categories list (the initial screen on the Songs tab as shown below). If your files do not show up in SongBook, check whether they have one of the supported file extensions (see above).

By the way, your initial post in the thread makes me think you want to factory reset the device. That's why detailed explanation is very important. We can't see what you're doing.

Search for iPhone or iPad user guide in iBooks and you should find the iOS 12 guide.

Start here for a manual, https://help.apple.com/ipad/12/. It is also available in iBooks.

Madairarc wrote:

A user group said I need to refresh it by

opening it and clicking on the round arrow in the upper Left corner.

By opening what?

You will lose everything if you factory reset. I don't think factory reset will resolve your problem syncing Dropbox with the app.