You need an existing working version of v8.6.x (or newer) and the license key for the Mobile Module.

If you have such a license key already it will open up the administration of the Mobile Module and you can start creating your rules.

When this is confirmed you will need to install the Exchange agent on your Exchange Server.
If you have one server you just install it directly on this server.
If you have a clustered environment, you need to install it to cover each outgoing message.

If you don't know the architecture of your Exchange environment or don't know how to do this, then install it on each node that has HUBtransport role.
If you use Edge server, then you can install it only on this server if it is responsible for sending.