Checking Moisture Content

I had a relative that cut down a standing dead cypress tree (I think it's red cypress). He gave it to me and I had it milled into 5/4 boards. The widest ones are about 28" wide, and they look pretty nice. They are stickered and stacked and air-drying under cover at the mill. Since I am new to this, I have a question about checking the moisture content with a moisture meter. I got one and am not familiar with the process.

BTW, I ended up with about 300 bf for a cost of a bit over $600...

Checking Moisture Content