I have found theses on a similar subject to my own, and want to use their references with my own text and a similar flow. Is this plagiarism?

There are actually two concerns here:

1. Is it plagiarism?

   The authors of the theses you are reading have made an intellectual contribution: interpretation, summarization, organization and curation of references.

   If you just paraphrase their work, the reader will assume that you carefully curated that list from the literature and that you came up with that "flow" yourself. If you don't tell the reader otherwise, it is plagiarism.

   However, you can avoid concerns of plagiarism by citing the thesis from which you got got this, and making it clear to the reader what is your original work (the text) and what isn't (the reference list and the "thought flow").

2. Does it satisfy expectations for a masters thesis in your department?

   Generally, a masters student is supposed to be able to read and curate the literature, and place their work in the context of the literature (the "thought flow") themself.

   If you copy this from someone else, even if you cite them (so it isn't plagiarism), you may not be doing what's expected from you as a masters student.

You can do this:

"ThesesAuthorA [ref to their work] anaylsed the works of Bob [ref] , Jane [ref] , and Alice [ref] using some_method and found that their_conclusion. However the evidence can also be interpreted to show your_conclusion.

or this

"ThesesAuthorA [ref to their work] states 'direct quote of the thesis' in their analysis of Bob [ref] , Jane [ref] , and Alice [ref]. "

Either way you need to make it obvious that the conclusions are drawn from someone else's work, and that the references are only those required to support the points and arguments that you are making.

As @ff524 said this is your theses for your research project, so you are going to have to find, evaluate, discuss and defend your sources.