Chains do not often come in exactly the length you need, typically they will need to be cut to the nearest link and have a pin removed so that a master link can be installed. That's where a chain breaker tool comes in handy, they are designed to easily push out the pin in smaller chains. 520 and heavier chains will need the head of the pin ground down a bit before employing the breaker tool.
After you assemble your chain, you’ll need to oil it. Your chain needs oil for smooth operation but unfortunately, oil holds dirt and debris. Enter the chain brush! The stiff bristled brush will clean off all that gunk and you’ll be ready for a fresh coat of chain lube.