Taking a couple minutes to warm-up before you jump into practicing is the best way to ensure you're going to have a productive practice session. It gives your body and mind a chance to feel/think about the task at hand and allow you to be more successful while you are actually playing the music.
Currently, before you start playing, take 1-2 minutes to start with your bow exercises to make sure your bow hold looks and feels awesome. After a couple bow exercises, move to Eyes Open, Eyes Closed (EOEC) to warm-up the rest of your body. As you do this, you're making sure your instrument is properly positioned, your left hand is setup correctly, and your bow is moving correctly on the instrument. Be creative and have fun, and use whatever note and rhythm combination you need to clean up and prepare for the music you are about to play.
Here's what practice should look like:
Warm-up: 3-4 Minutes (Bow Exercises & EOEC)
Practice (Say, Sing, Play 5x): 13-15 minutes
Perform a piece for someone or play-along with the IPS app: 1-2 minutes
This week we get some more experience playing E on the D-String. The first piece is #27, which introduces string crossings while playing with fingers. #28 is an opportunity to try your hand/ear at composition. Then we are going to jump back to the arco section of the book to look at several more pieces that use just D & E to make sure you have this skill rock solid!