The simplest way is to follow the KL- Seremban highway and go straight all the way until you can see the "exit to Port Dickson" signboard, then follow the signboard and pay a TOL.

Then follow the signboard "to Port Dickson" again and then pay the second TOL (the distance between the 1st TOL and second TOL is around 1.5km) before entering the highway to Port Dickson.

Go straight until you can see the signboard "Lukut" then turn left to follow it to exit to Lukut. Go all the way straight and you will find yourself in a T-junction and there's a signboard saying turn right to Lukut. Follow it and then around 3-4km you will reach Lukut.

Hope my instructions is clear enough.