Help Installing propietary AMD Drivers on Ubuntu 18.04

I know that this question has been posted already (kind of) but those seems not to apply to my case, as with the tutorials I found online, seems to be different.

So I have a samsung laptop (AMD APU A6-1450 with integrated grapichs) i was trying to play some games, then i realised that CSGO for example runs at 15/20 FPS, which make me wonder, so i check and seems I'm using the ubuntu open source drivers.

I went to AMD website and download my drivers from their website, which for my current APU and GPU its "Crimson Edition 15.12 Proprietary Ubuntu 14.04 x86_64" so I downloaded and here is the first problem, I realize its a .deb package, not a tar.gz with a .sh file inside to run (which shows up in all the tutorials online to install propietary drivers), i check just in case the .pdf in AMD website which said would help to install the drivers, but that pdf is beyond complicated and misleading, (and also refers to a .tar.gz file with a run file inside, not a deb package). Anyway i thought it would be easier since its a deb, so i tried to install it by dpkg -i amdblablabla.deb fail becasue fglrx-core dependence not installed and other "libtq4" (something like this i forgot the name) also "missing dependecies or not installed".

So i tried, sudo apt-get update and sudo apt-get check and sudo apt-get -f install

but it didnt help (dependecies didnt installed) it just suggets me to delete the fglrx deb I installed previously

I tried the following (according to AMD pdf file if missing dependencies) sudo apt-get build-dep fglrx-core and apt-get build-dep "libtq4" which are the dependencies missing, but fail because it didn't recognice the packages or doesn't found those packages.

So here is where I stop because I fail to find a tutorial for a .deb package to install AMD propietary drivers, I'm missing something here? or what I'm doing wrong, i ask becasue i'm not that knwoledged of ubuntu, i read somewhere that first you have to uninstall the open source drivers or purge it, but not Im not 100% sure if i have to do that for my case, since my ubuntu is very clean install...

Anyway thank you in advance. :)