A nymea installation requires 2 parts. The first step is to install nymea:core on a machine that’s running in the network all the time. The second step is to install nymea:app on the devices that are used to control nymea:core. This can be all on the same device where nymea:core is installed, or distributed across multiple devices like mobile phones, tablets and laptops.
A typical nymea setup will have nymea:core running on a low power host, such as a Raspberry Pi which is connected to the local network and a multitude of client installations on various other devices. For example every member of the network having nymea:app on their mobile phone, PCs etc.