then the next step of evaluating your source is asking:
Great! Start reading and taking notes.
It is crucial that you understand what you read, especially since you are reading it in order to write about your findings. You cannot write about anything competently if you do not understand what you are saying.
Don't worry, you can either find a different resource that is both credible and relevant -- or if you really want to use this one:
Figure out why you don't understand it yet.
For these problems, doing a little background reading should help, and once you've gained the vocabulary, concepts, and contexts, you'll be able to understand it better. Reference articles, book introductions, some news articles, and articles written for a general audience and published by reputable periodicals are great places to start.
If, however, it is too hard to read overall (feels like the author is almost writing in another language) it may be better to find a different credible, and relevant source.
To help you find a different source, consider: