After re-reading verses 17-18 several times, I’ll re-phrase the question slightly. Are there any extra sources that tell us what St Paul was doing in Arabia and Demascus? Was he being 'instructed or preaching or something else?
Galatians 1:16-19
Douay-Rheims 1899 American Edition (DRA)
16 To reveal his Son in me, that I might preach him among the Gentiles, immediately I condescended not to flesh and blood.
17 Neither went I to Jerusalem, to the apostles who were before me: but I went into Arabia, and again I returned to Damascus.
18 Then, after three years, I went to Jerusalem, to see Peter, and I tarried with him fifteen days.
19 But other of the apostles I saw none, saving James the brother of the Lord.