Q: How do I close down apps on my iPad to save battery power ? Cant remember !!

Double tap the home button, and then swipe the apps up to close.

1. Double-click Home button

2. Swipe app preview upwards to close app

Suspended apps are using very, very little battery power. I almost never close apps completely and may have 30 or more apps suspended in the multitasking display at any given time. I can put my iPad to sleep for hours with virtually no battery drainage at all,

Take a look at this. If you are that concerned about using battery power, turn off background app refreshing,

Understand multitasking and background activity on your iPhone, iPad, or iPod touch - Apple Support

Most apps close automatically when you tap the home button and go to the next app. Force closing is usually only nesessary if the app is misbehaving. The only exception are the music apps. With their ability to play in the backround they always need forceclosing.