The effect about empty string in NFA

Question

I am learning Sipser's book "Introduction to the Theory of Computation" on automata theory. I am confused about the effect about empty string in NFA when reading the first chapter

There is a state diagram of nondeterministic finite automaton N1

If we feed string "010110" into N1 Then as showed in the book, the computation process will be

I can't get understand that when N1 read the second symbol from string,that is "1", the state "q1" should split into "q1" and "q2". Why there exist also "q3"

The principle of computation involving "empty string" is described as "If a state with an symbol on some exiting arrow is encountered, the machine split into multiple copies without reading any input"

Answer 1

You can reach $q_3$ from $q_1$ by reading $1$ followed by $\varepsilon$ as follows $q_1 \xrightarrow{1} q_2 \xrightarrow{\varepsilon} q_3$.