Ask HN: Advice/resources on house interior construction/construction in general?

Hi, I am in the process of insulating the walls on the first floor of a two-story newly built brick house I own. The construction is not going well, I am quite late on schedule and have to continue into the winter, the construction workers I am able to hire locally are, so to say, not the brightest, and I lack the knowledge in this domain to call bullshit. Could you please give me advice or suggest any forums/books with practical info to better grasp the process of construction?

What's happening is construction workers are finishing putting in plaster on the walls of a 4 by 8 meter room. The spackle underneath was supposedly to become dry within a week under the use of gas heat pumps. Seems like this has not happened, and some parts of plaster are crumbling. The workers claim that the rest (spackle and plaster) is dry, so they are now applying a second layer of plaster to fix what requires fixing. After that they are going to start with white paint. What exactly should I do here?

Temperatures outside are about -15 °C, indoors with pump +26, and about +5 without.

Any resources or advice on this matter + stuff that may come in the future would be highly appreciated.