Establishing a PMO

There is not a "serious" certification to recommned. In fact, there is no sense in recommend a certification due to thre is not nothing special to create a PMO. If it is a supportive PMO then is more "simple". Supportive PMOs are mainly focused on providing project manager for each project. If you have a project management process in place then the only thing you have to do is provinding project managers for each project that follows that process and to assure that the process is following what some people call "governance". To stablish govenance take a look to stage gate process (https://www.stage-gate.com/stage-gate-model/). Very important is to understand what control points you need to implement and that is a matter to elicit requirements with the top management or portfolio managers (or whatever the way you call people that put the money -resources in geneal-) to create solutions.

I am sorry Sergio, I got the names mixed up! We are setting up a controlling PMO not a supportive one. We won't be having PMs assigned to projects, rather we are more into monitoring and controlling, setting governance, risk, coaching and mentoring, and reporting to top management and the board. Also, managing interdependencies, coordinate projects, assure compliance... etc

Just as discussed in Thomas slides, a value adding PMO.