Confused About Some Python Code for Team Selection

Hey everyone! I'm just starting out with coding and I'm currently working through a project from a book titled "Beginner's Step by Step Coding Course." I recently made a program that randomly selects players for teams and assigns team captains, which has been great! However, I've run into a couple of things in the code that I'm struggling to understand. Here's a snippet for reference:

```python
if response == "team":
team1 = players[:len(players)//3]
print("Team 1 captain: " + random.choice(team1))
print("Team 1:")
for player in team1:
print(player)
print("n")
team2 = players[len(players)//3:(len(players)//3)*2]
print("Team 2 captain: " + random.choice(team2))
print("Team 2:")
for player in team2:
print(player)
print("n")
team3 = players[(len(players)//3)*2:]
print("Team 3 captain: " + random.choice(team3))
print("Team 3:")
for player in team3:
print(player)
print("n")
response = input("Pick teams again? Type y or n: ")
if response == "n":
break
```

My specific questions are:
1. Why does the code use double slashes `//` instead of a single slash `/` for dividing the players into teams?
2. What's the purpose of multiplying by `2` for the selection of teams 2 and 3? Is there a particular reason for that in terms of algorithms?

The project imports the "random" module, so I'm also curious if this syntax relates to that in any way. Any help would be really appreciated!