VLOOKUP betwen sheets

In sheet 1 I have 4 columns (A is empty , B,C,D)
in sheet 2 I have 3 columns (A,B,C)

I want in sheet 1 , A column (empty) use the VLOOKUP and if Bn (in sheet1)= Am (in sheet 2) write “ok” in An , else this shell still empty

sheet 1
sheet 2

put in sheet 1 A15 =”ok”

if in sheet 2 not exist “Smith” A2 still empty

thank you for your attention

Hi, have a look at the attached file, I have used the function MATCH to check for the name existing in sheet 2.
Let us know if it helps.LOQ_20190810.ods
I am using Win 10 build 1903, and LO

Thank you!!!
i like and your solution … very practice!!!

My friend you give me the idea and solution :

=IFNA(VLOOKUP(G2;$Sheet2.$A$2:$C$100;1;0);" ")

or you can choose any column you want to display (1,2 or 3)

thank you very much