Hello!!! So i am trying to choose how many lags to do, and someone helped me with some code but i don't know how to interpret it..
I have daily data for stock returns for two cities

they've looked at the PACF and ACF (code is: "ac" and "pac") as well as done:
"dfuller returns, lags(12) regress"

they also put all 12 lags in the regression, like this:
"regress returns cloud temp sunhour l(1/12).returns i.month"

How do I choose the number of lags using all this? is it with whichever has a significant p>z value ?
or do i count on the pacf or acf graph and if so do i use pacf or acf?

they also did
lmalb returns, lags(5)

please help, im stuck on this!!