yeah_oh_yeah's questions

So I've been experimenting with Ubuntu on and off for a while, but I honestly have no idea what the hell I'm doing. So I have a realtek RTL8812bu WiFi dongle that I'm hoping to get working. I did some research, and came across this driver on GitHub that a couple people across two threads said worked for them:

At the bottom it said there is a new version here. So somewhere it said it was confirmed to work on kernels up to 4.16, so I checked and I'm on 4.15.0. But the problem I'm having, is what am I supposed to do? There is some installation guide at the bottom that is about as clear as mud to me since I don't know much.

I have a GTX 750 ti and I'm using Ubuntu 18.04. I have never had problems before with graphics drivers not working well. So before I installed drivers, I was getting massive amounts of screen tearing and lag. Afterwards, I still notice a lot of lag in animations (clicking "Show Applications", maximizing windows, minimizing windows, etc.) and sometimes when moving windows around or resizing them. When scrolling through web pages on browsers it will lag and I notice screen tearing. I have tried installing many different drivers, including the nvidia-375 and nvidia-384 drivers that are in the default Ubuntu repository. I also tried using drivers from the Graphics Drivers repo (https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa). No matter what I do, it never gets rid of lag in the animations or screen tearing within browsers.

I was trying to install my drivers for my graphics card, which is an AMD Radeon HD 6570, and when running the .run file, it first told me to download some packages first. Then i got another message telling me to install some other things, only this one doesn't make sense to me, as i am a n00b to Ubuntu. I have understood simple terminal commands like

sudo apt-get install <package>

but this is where being new kicks in, and i have no idea what to do...

Here's what it says. Can anyone tell me what to do, and help me make sense of what this says?

(Click this for a picture of the text)

ALSO, this MAY help. Here is the driver im installing: http://support.amd.com/en-us/download/desktop?os=Linux+x86_64

I get this error:

Running Steam on ubuntu 15.10 64-bit
STEAM_RUNTIME is enabled automatically
[2015-11-23 19:36:32] Startup - updater built Nov  9 2015 18:23:22
SteamUpdateUI: An X Error occurred
X Error of failed request:  BadValue (integer parameter out of range for operation)

When I try to run steam. What does this mean? (I'm pretty new to Ubuntu, so I don't have the hang of everything yet.)