Most of the Amigas in the wild spend recent years hidden in the attics and cupboards. There are multiple reports of people rescuing A500 computers from skips and garages. Chances are that hardware you got haven’t been stored in optimal conditions. Layers of dust (if only) and ageing components create deadly mix with effects ranging from various errors crippling your machine to serious motherboard failure.
I know you’d like to play games, watch demos or use utility software as soon as possible, but it’s of paramount importance to perform thorough hardware check up beforehand. It will ensure long and healthy life of hardware, preventing future faults and will benefit you with better understanding of Amiga hardware architecture.