This just shows the scenery that the author described in the first chapter.
In this scene, Lennie and George are walking along a long road after being dropped off a bus that left them far from their destination, a ranch in Soledad, which is why George is mad.
In this scene the roles of the characters are established. We know that George is responsible for Lennie because Lennie is very impulsive and does things without thinking before.
Slow down Lennie, don´t drink water so fast.
During this scene, we learn that Lennie likes to pet soft stuff like mice, but he can't measure his strength and ends up hurting the mice. This is also when we learn that they had to leave their old work because he had tried to touch a girls dress
Give me the mouse Lennie.
What mouse George?
During this scene, Geroge and Lennie are going to eat beans, Lennie tells George that he likes his beans with ketchup. This triggered something inside George, which is why he said what he did. Lennie says he could leave, then George apologizes and says that he likes having him around.
In this scene, George is telling Lennie about how they are different from the other workers because they have each other. He also tells him that they are going to get a little house and live off the fatta of the land.