When we first meet George and Lennie, the two primary characters in Of Mice and Men by John Steinbeck, they are clumping rather loudly through the brush and foliage near the river--or at least one of them is clumping. George Milton and Lennie Small are virtually nothing alike; however, when we meet them this is what we see.
They had walked in single file down the path, and even in the open one stayed behind the other. Both were dressed in denim trousers and in denim coats with brass buttons. Both wore black, shapeless hats and both carried tight blanket rolls slung over their shoulders.
In fact, however, they are nothing alike. George is a rather small, taut, intelligent man. Lennie, on the other hand, is a lumbering giant, and it does not take much time with him to figure out that he is mentally challenged. They are together (for a reason you will undoubtedly find out as you continue reading) in all things, and now they are going to set up camp near the river for the night.
The two men had to leave their last job (again for something you will read later), and tomorrow they will be going to their next one. They are traveling ranch hands. This means they do not really have a home of their own; instead, they travel from job to job, working on ranches in whatever capacity they are needed.
That is where they will be going tomorrow; for now, they are headed to a suitable spot near the river to set up camp for the night.
For excellent summaries and analysis of this novella, note the eNotes websites I have attached for you below.