A very tricky question you asked.
The first thing you need to get clear about is the practice. Just from your brief post it is difficult to say, but I would venture to guess that you view samatha and vipassana as two separate meditation regimens. This is an incorrect view. Samatha and vipassana go together and complement one another. Perhaps the following essay will help you to sort out this difference:
One Tool Among Many.
Second, choosing a specific teacher can be an intimate and personal endeavor. One should ideally take one's time with this process. Get to know the person first as a human being before becoming all caught up in the student-teacher relationship.
However, if you are referring to a more relaxed relationship of meditation guide to student, meaning that you could use some hands on guidance with how to go about structuring a practice in meditation and Dhamma study, then this is a horse of a different color. Keep your eyes open and read about different approaches to this until you find one that resonates with you. You're better off to just go slow with this process and let it take its time until you find a guide and approach that suits your inclinations and ability to make a personal commitment to the practice. Also, logistical considerations can often come into play. That is, you may locate a teacher/guide who lives in a different state or country from where you are.
The reason that you are hearing that it is best to "find a qualified meditation teacher" is because at certain crucial stages of the practice, it is best to have hands on assistance with the practice in order to help you smooth the way through these stages.
At any rate, if one is not already aware of this, one should become informed about why there exists a need to practice at all. The following might help to clarify such a prerequisite:
Going for Refuge. In conjunction with that if you haven't already read it, the book by Bhikkhu Bodhi on
The Noble Eightfold Path, The Way to the End of Suffering should be of considerable help and assistance regarding the path which the Buddha taught.
I'm sure others here may have differing opinions about this. All the best to you.