Google Forms may sound daunting, but it really is so easy to use! My Google Forms 101 post can help you learn more about making a Google Form, sending it out to students, and handling the results.
The video below shows specifically how to make a self-grading quiz using Google Forms. It shows the different question types you can use and explains how the answer key works. You'll also learn how to view the responses and enter scores for questions it can't grade automatically. Between these two resources, you have everything you need to start building Assessments with Google Forms.