Cleaering RAM just means you're forcing the iPad to restart the app from scratch. Sometimes errors creap into a running app. Just like any other project that goes awry, sometime the easiest thing to do is throw it out and start over.
So, in more detail. You double press the Home button (round button on the front). This will show you a side scrolling list of recenlty used apps. Swipe up on the app you want to clear. Tap the Home button again to go back to the main screen.
Reseting the iPad is the same thing, but you're doing it to the entire iPad; forcing it to start everything clean. It's even a little more effective than turning your iPad off, then back on. Think of it as restarting with swift kick to the tush just to make sure the iPad gets the message.
It's easy to do. You just hold down the Home and Power (on top right edge when home button is at the bottom) buttons at the same time until you see the Apple logo. Let the buttons go and the iPad will finish rebooting. Done.
It is also possible for the app itself to get corrupted. In that case the app itself has to be thrown out and re-installed.
To do this tap-hold on the app (or any app) until they all start to jiggle (Apple's choice of words). A small (x) will appear in the corner of the app. Tap this to delete the app.
Go to the App Store and look under the Purchased tab. You should see your app with a small cloud and down arrow icon. Tap on this to redownload the app. It's free, even if the app cost money when you bought it. You can also search for the app and find it that way.
If you have a subscription or other paid content in the app you may have to sign back in, or restore purchases. If this is an issue, ask, and we'll see if we can help. It tends to be a bit different in each app.
If you don't have a copy, I recommend you go to the iBook Store (in the iBook app) and download the most recent version of the iPad User Guide. I think it is iOS 9.2. Browsing through it may give you a better idea of how the iPad works, and it makes a good refernce.