where is this battery icon thing with an arrow and what is a computer display

[east789]

trying to enable conservation mode but instructions to do so are way way over my head

 

[The Paladin]

using windows , good

click START, Control Panel, Power options , select (show other additional plans) and then select the bullet point power saver.
apply, there that was easy

if your using windows 10 menus, right click on the notification icon next to clock , the select all settings, in search box, type power, then select power plans, and select power saver.