The boys needed time to realize that they were in a safe, quiet, and less-stressful space and were not going to be roughly handled. All of us needed to get to know one another and establish trust. In order to do so, Aaron and I spent time sitting on the floor in order to hang out with them; if we stood up, the boys scattered and hid. (Understandably, humans loom over cats when they stand up. We needed to work slowly with these guys.) We spoke in low, quiet voices to the boys as another way for them to get used to us.
Garrus was the first to come out of hiding and tentatively approached us. We moved very slowly around the boys as to not inadvertently startle them. We let Garrus sniff us and choose on his own terms how to engage with us. If he wanted to come toward us for pets, he could do that but if he chose to back off and hide, we did not reach in after him. A few hours later, Charlie emerged from his hiding spot and timidly checked us out. We noticed that he first watched what Garrus did and followed his lead. We were both quite pleased when we were able to give the boys gentle pets and strokes. They jerked away if we put our hands on either of their bodies, even to give scritches, so we worked very slowly, read their body language closely, and took our cues from the cats.
Garrus slowly started to explore his surroundings. He was the first to explore the chair and desk.
Charlie came out from his hiding spot!