Pandas add value from df to a new df using if

I have a first df as this:

Date(UTC)            Pair   Side    Price      Executed                 Amount    Fee
                        
2021-01-18 00:16:33 ADAUSDT  BUY    0.387870    120.1000000000ADA   46.58318700 0.000755330

2021-01-16 00:35:50 LINKUSDT BUY    21.924700   0.9100000000LINK    19.95147700 0.000361620

and I'm trying to create a second df importing the data from the first df. In the image you can se the logic that I want, and where I got so far.Image

Code:

d={'Pair':[],'Medium Price':[],'Total Amount':[],'Total Value':[]}
df2= pd.DataFrame(data=d)

def add_pair(pair):
    if pair not in df2['Pair']:
        df2['Pair']=pair
        
df2['Pair']=df['Pair'].apply(add_pair)
df2