how to build table relationships in a firebird database?
While I'm pretty sure you should redesign your database at first (and probably read something on SQL basics), you can get what you want with triggers :)

This one inserts row into daily collection with appropriate balance:

CREATE trigger masterlist_ai for masterlist
active after insert position 0
AS
begin
  insert into "daily collection" (  "date",     balance)
                        values (new."date", new.balance);
end


And this one updates balance in masterlist after updates of daily collection (assuming date is the primary key):  

CREATE trigger "daily_collection_au" for "daily collection"
active after update position 0
AS
begin
  update masterlist
  set balance = new.balance
  where "date" = new."date";
end