Google Sheets – Using CHOOSE with ArrayFormula vs Excel

Assuming the columns you have are C-G, entering

=arrayformula({C2:C, D2:D & E2:E & F2:F, G2:G})

in the cell H2 will have the desired effect. The arrayformula indicates that in every row, one should have three entries: one from C, one is concatenation of D,E,F, and the last from G.

It looks like you're trying to create a heading in row 1, then below it, run a vlookup if there is a value in column B - This works

={"Country";arrayformula(if(len(B2:B)>0,vlookup(D2:D,FBlookup!$A$3:$B$20,2,false),))}