The markings in the triangles corresponding sides and angles indicate that those have the same measure.
The marks on the sides are called "tick marks", the sides with the same number of tick marks will be congruent.
Sides AB and ED have one tick mark each, this indicates that: AB=ED
Sides BC and FE have two tick marks each, this indicates that: BC=FE
Sides AC and FD have three tick marks each, this indicates that: AC=FD
The same occurs with the angles, the number of markings indicate that they have the same measure, so:
∠CAB and ∠FDE have one marking, this indicates that: ∠CAB=∠FDE
∠ABC and ∠DEF have two markings, this indicates that: ∠ABC=∠DEF
∠ACB and ∠DFE have three markings, this indicates that ∠ACB=∠DFE
We can determine then that:
ΔABC = ΔDEF