I have this small subquery that runs in teradata
select BASE ,
CUR, CVGE from Stg_Cv
where k_acctN in(select MacctN from
Tg_Cv
where acct_Id in (select Prod_Id
FROM Cv_Unit)

and I want to run it in DMC what is my steps or how do i do this

You can just type a subquery in a WHERE condition in the calculator.

OTOH in 7.7 for a subquery in the FROM list you add an SQL object to the flow.