what will i need (tools, parts) to replace timming chain guide.

my car started running half idle and stalling so on... found out about these plastic timming chain guides had to be replaced. i checked it. it's broke. the car still runs even though i'm no longer driving it cause i hear horror stories about if it jumps time. i wonder have i done damage to it already? because when i pull the coil wires from the passenger side of the motor(same side as the broken guide)it does not change idle of engine. I know the motor only has 26000 miles on it. i need to know what i need to get(besides a book) to fix it? do I have to chang tentioner/s also, both sides? timming chain/s. i know i need a tool to hold it still? thank you