Insert/Updated SP From Multiple Tables

How do I insert unrelated statistical data from three tables into another
table that already exist with data using an insert or update stored procedure?
OR...
How do I write an insert/Update stored procedure that has multiple select
and a where something = something statements?

This is what I have so far and it do and insert and does work and I have no idea where to begin to do an update stored procedure like this....

CREATE PROCEDURE AddDrawStats
AS
INSERT Drawing (WinnersWon,TicketsPlayed,Players,RegisterPlayers)

SELECT
WinnersWon = (SELECT Count(*) FROM Winner W INNER JOIN DrawSetting DS ON W.DrawingID = DS.CurrentDrawing WHERE W.DrawingID = DS.CurrentDrawing),

TicketsPlayed = (SELECT Count(*) FROM Ticket T INNER JOIN Student S ON T.AccountID = S.AccountID WHERE T.Active = 1),

Players = (SELECT Count(*) FROM Ticket T INNER JOIN Student S ON T.AccountID = S.AccountID WHERE T.AccountID = S.AccountID ),

RegisterPlayers = (SELECT Count(*) FROM Student S WHERE S.AccountID = S.AccountID )

FROM DrawSetting DS INNER JOIN Drawing D ON DS.CurrentDrawing = D.DrawingID

WHERE D.DrawingID = DS.CurrentDrawing
GO