Return all id's from table in store procedure

I'm continue discovering SQL and store procedure, having trouble that @feedid is returning only 1 id, but it have for ex. 20. How to return array of id's?

CREATE PROC spGetItemsByUser
    @userName NVARCHAR(50)
AS BEGIN

    DECLARE @userId INT,
            @feedId INT;

    SELECT @userId = ID
    FROM users
    WHERE name = @userName

    SELECT @feedId = feedid
    FROM userstofeed
    WHERE userid = @userId

    SELECT *
    FROM feed
    WHERE ID = @feedId

END