Las Cascadas Damajaguas are off the main road that travels from Santiago to Puerto Plata. If you travel from either of these cities on a non-express "guagua" it is possible to be dropped off at one of the entrances. However this depends on the local knowledge of the "chofer" or "cobrador" on the guagua. Therefore it may be better getting off at Imbert and taking a taxi or motoconcho to the falls, if you know the value of local transport you can avoid being "ripped off".
Entrance to the falls is via Sugar Cane fields just past "Ingenio Amistad" (the sugar factory) on the same side as the factory if going towards Santiago from Imbert.
To find the falls and to get up and down the falls safely it is advisable to take a Waterfall Guide. Again one has to deal sensibly for the cost of the guide and not get taken. I can highly recommend one called " Peto or Tronco".
The guides hang out at a house across the road from the sugar cane fields or at the river "Bajobonico" which you have to cross to enter the lane to the falls.
Take waterproof camera, two teeshirts, bathing costume, towel, shoes that you can get wet and dirty (no flipflops) and can swim in (shoes are available for rent there) and take small change for drinks, there was a small shop, and tips. Do not take valuables with you as there are a lot of people around.
Had been there myself many many times. Enjoy what I never attempted, the great adventure of climbing the falls.