Teaching young pre-school students is a very difficult and challenging assignment.
My recommendation is to use lots of visuals, pictures, and music to teach vocabulary.
For Classroom Management, it is important that you have structured activities during your class time. You might consider setting up different center activities that students could rotate through during your instructional time. These center activities should last no more than 10-15 minutes for each center.
Remember that these students need time to play and learn how to socialize with each other.
A good source of instructional material that includes music and also teaches many different concepts such as days of the week, months of the year, colors, shapes, parts of the body, etc. can be found in using Music from Greg and Steve. Their web site address is www.gregandsteve.com