No need to be afriad.
In most case when ordering a new battery you can pay a few bucks more (if not included) to get the tools you need.
The replacing is straight forward and the hardest part is to get the glued on batt pack off the circuit board - if in doubt just cut the old battery pack sidewas (very carfully!) with a knife.
This way you take the batt out of the plastic foil and leave the foil attached to the circuit board.
A quick warm up with a hair dryer will soften the glue so the remaining foil can be removed.