Here the simplest example that I can create:
Create a loop with object iterator:
when you can add a "Invoke subprogram" node
Put here Separate Text Object. It will breake apart your text and in loop we will transform text letters one by one
Next, add animate Matrix node. This node will create a transition beetween some object (I created an empty), end each letter, that we grab from loop. To get transform matrixes, use Object ID Key node (to get initial transforms of letters) and Object Matrix Input to get empty's position and scale.
In animation node you can set duration of animation of each letter an setup interpolation.
Next, it's need to add time info node to set time to animate node.
To give each letter offset in time add 2 Math nodes. One to multiply Index with offset in frames, second - to add this offset to time:
and finally it's need to apply this transform matrix to the object, use Object Matrix Output Node:
Don't forget to connect "object" to Initial Transforms and Object Output!