Where in this sentence is there a grammatical error?

"by reading history we come to understand that civil wars have occurred in many countries including england, spain, and russia."

Every customer that enters a sunfun retail location should be treated with kindness and respect. when someone comes in: 1. approach the customer and ask if he or she is looking for a specific item. a. if the answer is "yes," the customer find that item. b. if the answer is "no," let the customer know you're there to should the need arise. 2. if a customer has been browsing for about 15 minutes, respectfully check in again to see if he or she needs . 3. if a customer is holding clothing, ask if he or she would like you to set up a dressing room how is this section organized? by order of importance point by point compare and contrast step by step