Sorry if it is a newby question, im new to quantopian.
Im trying to replicate the alphales results to understand them, but I'm not beeing able to do it.

factor_data = run_pipeline(make_pipeline(), startDay, endDay) #build factors

dfAAPL = get_pricing(symbols('AAPL'), start_date=startDay, end_date=endDay) #get apple Pricing  
aaplResults = factor_data.xs(symbols('AAPL'), level=1) #get just apple factors  
df = dfAAPL.join(aaplResults) # join aaple factors + price  

I asume the returns are calculated:
Future Open / Today Open - 1

So I make the calculation

days = [1,2,3,4,5,10,15,20]  
for d in days:  
    returns ='{}DRetun'.format(d)  
    df[returns] = df['open_price'].shift(-d)/df['open_price']  
    res = df[df['Factor'] == 1]

    print(returns,(res[returns].mean()-1)*100 ,(res[returns].mean()-1)*100/d) #maybe its was the mean return by days?  

Foward, Return, Mean Days Return
('1DRetun', 0.24037338368763095, 0.24037338368763095)

('2DRetun', -0.18177306856032027, -0.09088653428016014)

('3DRetun', 0.28722005736183664, 0.09574001912061221)

('4DRetun', 0.5946041417401515, 0.14865103543503788)

('5DRetun', 0.8046724143346617, 0.16093448286693235)

('10DRetun', 1.1221817218125096, 0.11221817218125096)

('15DRetun', 1.2784627411053462, 0.08523084940702308)

('20DRetun', 2.4049766319204746, 0.12024883159602373)

But the pipeline Results are

pricing_data = get_pricing(  
  symbols=factor_data.index.levels[1], # Finds all assets that appear at least once in "factor_data"  
  start_date=startDay,  
  end_date=endDay, # must be after run_pipeline()'s end date. Explained more in lesson 4  
  fields='open_price' # Generally, you should use open pricing. Explained more in lesson 4  
)

merged_data = get_clean_factor_and_forward_returns(  
  factor=factor_data,  
  prices=pricing_data,  
  quantiles=None,  
  bins=[-2,-1,0,1,2],  
  periods = [1,2,3,4,5,10,15,20]  
)

create_full_tear_sheet(merged_data)  

---------------------------------------------------- -1D-----2D-----3D------4D------5D----10D----15D----20D
Mean Period Wise Return Top Quantile (bps) -0.080 / -1.058 / 1.157 / 1.136 / 1.428 / 1.568 / 0.871 / 0.812

I dont get it.
Is there some place where I can see what the alphalens results mean and how are they calculated?
What is Ann. alpha? What is beta? I know beta is how much my performances is linked to the performance of the market