Queries :: Append Data To Table?

I have a table called dbo.userinfo with a primary key called employeeid and a field named jobfunction.

i have an intermediate table named dbo.projectpositions with a primary key named projnumber and a foreign key named employeeid.

I have a 3rd table named projects with a primary key projnumber and a field called project manager.

I'm trying to append the Projects table so that any projects that a worker has worked on (dbo.projectpositions) that is listed as a project manager (jobfunction) will have their employeeid fill in the project manager field on the projects table. Looks something like this:

INSERT INTO Projects ( [Project Manager] )
SELECT dbo_UserInfo.JobFunction
FROM (dbo_UserInfo INNER JOIN dbo_ProjectPositions ON dbo_UserInfo.EmployeeID = dbo_ProjectPositions.EmployeeID) INNER JOIN Projects ON dbo_ProjectPositions.ProjNumber = Projects.ProjNumber
WHERE (((dbo_UserInfo.JobFunction)="Project Manager"));

But just can't figure out the next step to populate the project manager field...