Self Certifying for FCC testing
There are two ways to file for an unintentional radiator, with an SDoC or through an accredited laboratory.


  For equipment authorized using the SDoC procedure, it is not necessary
  to perform the testing at an FCC-recognized accredited testing
  laboratory (although the responsible party may use an accredited
  testing laboratory if it wishes to do so).  The testing laboratory that
  is used must maintain a description of the test facility, as required
  by Section 2.948(b).  The description of the test facility does not
  need to be submitted to the FCC, unless requested. Test reports must
  be signed by a representative of the responsible party with the
  authority to act on behalf of the responsible party. It is not
  necessary for the representative that signs the test report to be
  located in the United States.
  Source: https://apps.fcc.gov/oetcf/kdb/forms/FTSSearchResultPage.cfm?id=203240&amp;switch=P


The SDoC needs to conform with ANSI C63.4. So the methods to test and the requirements to setup your lab are contained in ANSI C63.4 (which is paywalled).

If you want to make your lab accredited, the information to do so is listed  here.

If your only doing this for one product, there are labs that will help you get an SDoC for under 1k$, which it might not be worth your time if only doing this for a few products.