I don't know what you have for tools but the way I have done it is use a fence on the drill press. I clamp the wood to it, drill and replace the drill bit with the insert installation tool. With the drill press UNPLUGGED I hand turn the chuck while applying downward pressure with the drill press handle. The wood never moves, so as long as the chuck and fence are at right angles to the table the insert goes in straight.
On hard woods I over drill the hole so the insert will fit kind of tight into the hole. Apply tape to the bottom side of the insert, put some epoxy in the hole and press the insert into place. The tape is so the glue does not enter the threads through the bottom of the insert.