Through a bank.
You need to go to a bank to solicit the ATM. If your specific location meets certain criteria (such as security, power availability,etc.), they will do a cost-analysis study to see if the location is profitable for them to proceed.
Best to go to a bank where you have some sort of relationship. As in all things in the Dominican Republic, if you have a good connection at a bank, all things are possible.
Good luck.