To place an ATM you need to work with a registered ISO (Independent Service Organization). Working with the right ISO from the beginning, I feel is pretty important. The ISO brings together a few things. They have the relationship with the processor, relationship with the sponsoring bank, the branded networks, and they often provide technical support along with equipment sales.
ISO - The ISO brings together all the following elements, they also hold liability for compliance and managing IAD's
IAD - Independent ATM Deployer, they is someone who places ATMs, they are required to work with an ISO
Processor - the processor or the "switch" grabs the transaction from the ATM and directs it to the correct network.
Sponsoring Bank - Because the ATM is a financial instrument, it requires a registered bank to bring the transactions into the banking world. This is required by the Federal Reserve banking rules. Sponsoring bank often oversees compliance with Federal Regs.
Branded Networks - For older folks, years ago, you will remember if you had an ATM card, you had to go to the Network that your bank belonged to. In my case in Massachusetts, it was Yankee 24. Most networks are interoperable right now, meaning they have agreements to hand off transactions to one another. The network's job to work with the authorizing bank to acquire the transaction from the processor and direct it to the cardholder's bank for approval or denial.
In summary, they first two things you want to do is, Find the right ISO to work with and find a bank willing to open an account for you. Each bank is different and may require different things. Many banks will not want to work an ATM operator, for various reasons.