Decky

Regular Installation

Ideally, the latest PowerTools release can be installed from https://beta.deckbrew.xyz/ after installing PluginLoader.

If you haven't yet, install Decky Loader by following their steps: https://github.com/SteamDeckHomebrew/decky-loader#installation
In gaming mode's Quick Access Menu, you should see a new option for plugins (a cord plug). In that menu, click on the market (top right).
Find & install PowerTools from the list. A pop up should appear to confirm you'd like to install it (sometimes it takes a few tries for the pop up to appear).
Wait for PowerTools to download and appear.

Regular Uninstall

In gaming mode's Quick Access Menu plugin tab click on the cog (top left).
Go to Plugins, and click the trash can beside PowerTools

Manual Installation

If you are having trouble with getting that to work, you can install the latest version from GitHub manually.

Do steps 1 & 2 from Regular Installation
In gaming mode's Quick Access Menu, you should see a new option for plugins (a cord plug). In that menu, click on the cog (top left).
Copy the link from the latest release archive into the URL box (e.g. for v0.7.0: https://github.com/NGnius/PowerTools/releases/download/v0.7.0/PowerTools-v0.7.0.tar.gz).
Wait for PowerTools to download and appear.

Manual Uninstall

I'm sorry to see you go, but all good things must end. This is quite simple:

In a terminal, run sudo rm -rf ~/homebrew/plugins/PowerTools. Be careful to type that exactly, otherwise you may delete something else that you didn't mean to.

Optionally, remove saved PowerTools settings and other data by running sudo rm -rf ~/.config/powertools. Once again, be careful to type that exactly.