The method section of your work will consist of systematic searches. As with any other method, you should describe the steps you have taken. This means you are encouraged to report where and how you searched, as well as how you selected the articles included in you review.
No, you will likely conduct many searches before finding the "perfect search" (i.e., a search that yields a manageable number of hits and seems to provide relevant material to select from). The searches you report should only include those that lead to the articles used in your review.
The search template below can assist you in documenting how you conducted your searches to arrive at the 6-12 articles to include in your review. Additionally, the template can be attached as an appendix to the methods section for added clarity in your reporting