Any single-speed or standard derailer chain can be connected with a chain tool. Narrow 9, 10 or '11 speed' chains have plates that are too thin to make this a reliable process and connect with special links that are supplied with them. Some chains – for example Shimano - have to be broken and reconnected with a special pin. Others with a trick link that can be dismantled by hand.
Direction Of Travel
Make sure the replacement pin will be in the leading hole of the outer link in chain’s direction of travel. The replacement link should be in the forward hole in the outer link, in the chain’s direction of travel.
Line up the holes and push the rounded end of the replacement pin into the link.
Put The Chain In The Chain Tool
Put the chain in the chain tool in the position furthest from the driving punch.
Drive the pin into the chain by screwing in the punch on the chain tool. Push it until the connecting pin is aligned with the outer link surface from the side that the pin is inserted.
Remove the chain tool. Check the head of the pin is flush with the plate by touch.
Break off the excess part with a pair of pliers.