Watch the Holding the Bass and Tuning online guitar lesson by Brad Carlton from Blues Bass
There are two parts to this lesson. In the first half you'll learn how to hold the bass. Since the bass is a rather large instrument with a longer scale length than the guitar, it's important that you hold it in a manner which will allow you access to the notes on the neck.
The video will demonstrate this with many suggestions as to what to avoid so that you are as comfortable as possible.
In the second half of this lesson you will receive some tips on how to tune the bass. It's a good idea to use an electronic tuner which is compatible with the lower frequencies that exist on the bass.