In an online situation (devices powered and connected) the amps should appear in the "discovered ALControl devices" list in the Devices tab. Note that with the "Network > select network interface" control it's possible to select on which network the scan/auto discovery takes place. This is useful when having multiple network interface cards installed. Now you have two options for starting a project. Either you open an existing project created before (System > open or ctrl+O) The amps are set back in the state you saved them in. The amps in the discovered device list that are part of this project are removed from the list.
Units can be visually identified by pressing the "blink logo" button and select the device in the "ALControl devices in project" list. You can select multiple devices at the same time to identify a group of devices.
You can also move the discovered amp to the project space by pressing the "move to project" button, while having the amp selected in the list. The ALControl settings are synced to the amp's settings so presets input source etc is synced from the amp to the remote, in the grouping tab channel list you can open a channel and directly control it. If you need a different setup proceed as you would have added the amp manually.
Note that it might be necessary to change output mode. You can select multiple units and change output mode however units need to be of the same type (the S3 has different output modes compared to the S10 for example) Changing the output mode sets all presets to empty no signal can come out of the amp anymore, this is important because active presets can have tweeters directly connected to a channel! If a unit with channels in a group changes its output mode the channels will be removed from the group.
You can change the IP address of a device by double clicking the entry in the "ALControl devices in project" table. If the device was online it will move back to the "discovered ALControl devices" list and the changed unit will appear offline, until a unit with matching IP address is connected to the network.
Proceed to create groups to start making groups.