olenazh is correct. Your lab won't be accredited unless you have a third-party certification and personnel conducting testing are certified. Accreditation can be a real headache and really only worthwhile if you have customers that require accredited testing results.
No real manual or guide that I know of, but you have to first determine what testing you want to do in-house. A good resource can be the AOAC official test methods.
Once you determine the testing you want to do in-house you have to source materials and equipment. Get quotes for the costs of the materials and equipment and compare that, including labor cost, to the cost of testing in an outside laboratory. You also have to account for turn around time on the testing results. In many cases in-house testing is faster which can be attractive depending on the company and the testing.