When you make the first request to the 'Get all companies' endpoint, the response will contain an . offfset field that will include a numerical value. To get the next page of results, you want to take this value and include in in the offset query parameter when making the next request. The next request will include a new offset, which you include in the third request, and so on and so forth.
I've also included the developer docs for the 'Get all companies' method, for reference:
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