can someone explain to me what did he do at 2:58 and all the things with step[0] step[1]

Right, you know that enumerate() takes a list and returns an enumerate object containing tuples with the elements of that list numbered according to their indexes, i.e.:

animals = ["bird", "turtle", "cat"]
new_animals_list = list( enumerate(animals) )
# new_animals_list = [ (0, "bird"), (1, "turtle"), (2, "cat") ]

When the teacher uses enumerate() in that loop, he prints each one of the function's return value separately. Just like I'll do with my animals list:

for animal in enumerate(animals):
    print("{}: {}".format(animal[0], animal[1]))

When the loop runs for the first time, animal will be the following tuple: (0, "bird"). Using index notation, I access the tuple's elements (animal[0] and animal[1]).

Finally, the .format() method takes what's inside the parenthesis and replace the curly brackets ({}) in the string. The first pair of curly brackets is replaced by animal[0], that is 0, while the second pair is replaced by animal[1], that is "bird".

The same happens to the tuples (1, "turtle") and (2, "cat").

# Which results in:
# 0: bird
# 1: turtle
# 2: cat

Hope that helps! (: