Both men (Peter and Paul) attended the "Council of Jerusalem",
the first known meeting of the leaders of the church, including
Apostles and Elders. It occurred about 50 AD.

During these meetings, it is reasonable to construct that Peter
and Paul had several "one-on-one" sessions.

Probably, Peter shared with Paul, in detail, his experience at
Pentecost, when the Holy Spirit came upon the gathered. Then Peter
got up and gave "a fiery sermon". om which three thousands repented;
and were baptized.

And, Paul shared with Peter, in detail, his Damascus Road experience;
and his first Missionary Journey in 47 AD.

From page 320, Always Growing in the Faith, by Gene Dirr.
Available at www.amazon.com.