We use the = when we talk about numbers. When you solve an equation, you get x=#.
We use the word CONGRUENT Example: if AB and BC have the same length, we write AB

Two quick words to know:

Two quick words to know: midpoint and bisector.
A midpoint is exactly what it sounds like, it is a point halfway in between two other points. In your picture, T is the midpoint of SU.
Since T is halfway in between S and U what does that mean about the lengths of ST and TU?
THEY ARE THE SAME!!!!!
What do you think the little tick marks mean in your picture of SU?
They mean those pieces are the same. You can put as many tick marks as your want, as long as the pieces that are the same have the same number.
A segment bisector is a line that goes through the midpoint. So if there was a vertical line that went through T it would be a segment bisector.