How to Fix Folds of Skin from Tummy Tuck?

It is too early to do anything.
Wait and observe. Commonly skin will shrink when it is gathered, a process we call apoptosis.
The only alternative to remove loose vertical skin is to perform a vertical scar which many of my patients find objectionable. They would prefer loose vertical skin rather than a vertical scar. Of course, you may have different preferences and so I am speaking in generalities.
It is also possible that by making your scar longer, you could pull the skin outwards but this will not likely remove all the loose vertical skin.

Your result from your tummy tuck surgery tells me that you were very thin and had very loose skin over your abdomen, an indicator that you worked very hard to get your figure back on your own! I can also see your stretch marks in the photo that tell me that you were very overstretched. This surgery result shows that you had excess skin around your middle as well as up and down. Tummy Tuck generally takes care of the up and down excess but not the all around looseness. This surgery is all about "tailoring" the skin and unfortunately you ended up with "gathers" in the center that have to shrink down to smooth out.
So, your best bet now is use compression longer (try a snug waist cincher available at large department stores) and ask your doctor for some special compression foam used for liposuction patients to help compress the area further. if that is not successful over the next few months, you may need to consider a revision with a central vertical scar or revision of the scar itself to ease out the gathers over the entire scar to make them less noticeable.
Good luck and stay positive!