There’s nothing wrong with saying “they walked”, but if you want to mix it up or be more specific, here are some alternatives:
| Strolled | Walk at a leisurely pace. | 
| Sauntered | Walk in an idle or leisurely manner | 
| Meandered | Slowly, aimlessly, often with twists | 
| Trudged | Walk with effort or reluctance | 
| Ambled | Walk at a slow, easygoing pace. | 
| Strutted | Proud, often arrogant or bouncy walk | 
| Treaded | Walk with a careful or cautious step. | 
| Prowled | Walk stealthily like a predator | 
| Scurried | Briskly or hurriedly, often with small steps | 
| Strode | Long, decisive steps | 
| Pattered | Light, quick steps, often kids or animals | 
| Marched | Regular, steady, with purpose/confidence | 
| Scampered | Move quickly with playfulness or fear | 
| Moseyed | Walked in a relaxed, unhurried manne | 
| Paced | Back and forth in a regular, measured way | 
| Hobbled | Walk with difficulty, often due to an injury | 
| Shuffled | Short, dragging steps. Shy or reluctant. | 
| Slogged | Walk with effort, often through mud | 
| Tramped | Walk heavily, often over a long distance | 
| Traipsed | Reluctantly or without a clear purpose. |