Updated FAQ (markdown)

FAQ.md

@@ -4,6 +4,30 @@ PowerTools interacts with the system in roughly the same way as outlined in [her
 PowerTools does not save any data by default; it reads and writes to the SteamOS system (mostly the Linux kernel).
 Since no data is saved, a reboot will reset all PowerTools settings back to default.
 
+## Why use PowerTools?
+The settings made available through PowerTools allow you to tweak your Steam Deck for the best performance and/or battery life.
+PowerTools can be great for emulators which use too little performance, or for heavy games that use too much power.
+
+## How do I optimise my settings for a game?
+A good first step is to turn on the performance overlay to see what resources are being used by the game.
+Then change the settings until the game is using the resources more effectively.
+This is mostly trial and error, but here are some tips:
+- If only a few CPU threads are being used heavily at one time, try reducing the amount of CPUs available so the remaining threads can run at a higher frequency
+- If the CPU is mostly idle but the GPU has high utilization, try reducing your graphics settings
+- If you have higher-than-necessary FPS, try reducing TDP and frequencies to a point just before the stuttering starts
+- If the CPU and GPU have reasonable utilization but you're experiencing stuttering, try reducing the CPU or GPU frequency to give the other one more power
+
+## What is CPU/GPU frequency?
+The rate at which the processor does operations. 
+A lower frequency means the processor will do less over the period of time.
+This is a balancing act between power efficiency (where a lower frequency is better) and performance (where higher frequency is better).
+That's why frequencies fluctuate depending on the processor load.
+
+## What is PowerPlay?
+An AMD marketing term for their GPU (and APU) power management settings.
+PowerPlay is a Table (hence the initialism PPT) of power limits.
+Basically TDP.
+
 ## Why does PowerTools only let me select some values?
 There's a few reasons for this, depending on the values in question, but it all stems from limits imposed by (or to protect) the hardware.
 Most limits can be justified by the [specs of the Steam Deck](https://www.steamdeck.com/en/tech) or the allowed values for a specific kernel API.
@@ -30,6 +54,8 @@ Advanced Micro Devices: the company that makes the processor in the Steam Deck
 "Accelerated" Processing Unit: the marketing term used by AMD for a CPU with an integrated GPU
 ## CPU
 Central Processing Unit: the main processor, the Steam Deck uses one with Zen2 architecture
+## FPS
+Frames Per Second: the rate that images ("frames") are displayed on screen to create motion
 ## GPU
 Graphics Processing Unit: the graphics processor, the Steam Deck uses one with RDNA2 architecture
 ## PPT
@@ -38,6 +64,8 @@ PowerPlay Table: the power settings for AMD GPUs
 Quick Access Menu: the Steam Deck menu that comes up when you press the `...` button
 ## SMT
 Simultaneous MultiThreading: The generic term for making one logical core act like more than one core, equivalent to Intel's "hyperthreading".
+## TDP
+Thermal Design Power: technically the max sustained power usage of a computer chip, but is also colloquially used to mean power draw or limit.
 ## USDPL
 No, that's five letters