Hi
This kind of message that no appropriate appliance found comes up when you did not download the correct upgrade file or may be the Firepower manager (firesight) is not registered with sensor(firepower module) yet?
Please make sure Firepower module is registered with firepower manager and then download the correct update file for modules. As you need to go from 5.4 to 6.1, Its a long process.
If the set up is new, I would suggest following.
1: Upgrade the firepower manager to 6.1 first and bring upto date with all patches.
2: Simply reimage the firepower module directly with 6.1 and then register it with firepower manager which will be smooth and faster.
Rate if helps,
Yogesh