By default Action and Trigger node types are generated with the name and icon of the first action or igniter/trigger selected. You can rename them as you like the name won't be changed unless it's empty.
When a State Machine is created it comes with a Start Node which it runs whenever the State Machine is executed. This special node is the same as an Action Node.
Start Nodes can be changed if it's needed. Just create a new Action Node then right click and set the new node as the default node.
The Invoker target is always available in Start Node.
This type of node works the same way as a GC Actions List it can have as many actions as you like.
Once execution is completed it will move to the next Transition and Action Node if there is any.
Use triggers to execute specific action nodes.
Keep in mind that in some triggers the target Invoker can be used like On Player Enter. There are other cases like On Input Key where there is no invoker in this case it is required to use the Invoker variable from the State Machine. Click here to learn more
Add transitions to move between Action and Trigger nodes. These transitions can have conditions if the conditions are met they will keep going. If no conditions are assigned they will simply go to the next node.
To delete transitions select it on the graph then select the transition you want to delete on the list in the inspector the click on the minus icon.
Transitions can be disabled or turned off by enabling Mute toggle. This will make the State Machine ignore this transition.
Sub-State Machine Nodes
It is possible create Sub-State Machines when another level of organization is needed. Transitions from action or triggers to sub-state machines are possible as well, this will popup a context menu to select where the transition should go.
You can even drag and drop another State Machine and it will automatically create a copy and paste it as a Sub-State machine.