as noted above, you'll need a router, template, and a means to hold the template in place. I utilize a double-sided weatherproof tape to hold the template in place
if you have access to a drillpress, it will greatly ease your work if you utilize a Forstner bit to remove most of the excess wood prior to routing with the template. think of your routing work with the template as cleaning up and detailing the route
you will also need a drill bit long enough to reach the control cavity. I utilize a 3/16" bit like this
if you have no router experience - this is NOT the project to learn on. you must measure accurately for good results. if you slip or make a mistake you will either be heading to the hospital of finding a luthier to fix your bass.
all the best,
R