One piece collapsible chairs are permitted to be opened on Shabbos.

Chapter 315 Section 6

When placing two bowls down to support a third, if the purpose is for the third bowl [i.e. when the air is needed to cool the food in the top one], you shouldn’t put the bottom ones down first then the top, rather hold the top and insert the bottom ones under it.

Chapter 315 Section 7

As in the previous section, if it was a pile of seforim where the upper one is has no need for the air at the top, you can put the 2 bottom seforim first and the third on top of them.