Without a test kit you wont know if and when its cycled.
Well it depends on what fish you want to keep and their size!
Forget afew day it just doesnt happen that quickly whatever chemicals youve been sold and added. And your friend doesnt know any better by the sounds of it.
Research research research. I suggest you Learn and understand the nitrogen cycle of a fish tank before adding anything to the tank.
You can do what you want, i cant make you do anything and can only advise for the health of your fish. You can sling aload of fish into an uncycled tank but youll cause alot of suffering and probably have loses unless your willing to do water changes daily.
Be patient, cycle your tank and be a good man God to your fish.
You said your friend has some tanks? Get some used filter media off of him. Or go to his house with a small bag, fill it with his tank water and rince his sponges into the bag, then QUICKLY come home and pore the gundge into the filter directly. This will speed up the cycle ten fold.
Fish die belly upward and rise to the surface. It's their way of falling.