It's not a big deal to replace, but you MUST do it right or you will be doing more harm than good considering the risk of something breaking which would cost an engine.

You can remove the tensioner, connect the new chain to the old after breaking a link on the old, turn the engine clockwise as viewed from the front while a helper feeds the new chain seeing that it never looses its mesh with the top timing gear. Once the new chain comes around, disconnect the old one and put in place a permanent link. After that push the tensioner plunger all the way through and feed it one click in from the outside.

Good luck,