Field stripping the C7:
First you clear the weapon (individual safety precaution), but don‘t dry fire it afterward. Instead, set the selector switch to "SAFE". Push the rear takedown pin out to the right which will allow you to open the rifle up. Then pull the cocking handle back to remove the bolt carrier group (it‘s just called the "bolt" in CF parlance) from the upper receiver. Set the rifle down. Remove the firing pin retaining pin from the left side of the bolt (it‘s a tiny sucker, you have to be careful not to lose it), which will allow you to remove the firing pin itself. With it out, you can then remove the cam pin which is on the top of the bolt carrier by rotating it one quarter turn. This then allows you to remove the bolt itself from the bolt carrier group. Lay the parts left to right in order of removal, like in the pictures on the site. That‘s it.
To do the detailed strip, field strip the rifle and then remove the extractor pin and seperate the extractor from the bold. Remove the handguards, use the forward takedown pin to separate the upper and lower receiver, pull out the cocking handle and then remove the buffer and return spring (inside the stock, a tiny little pin holds it in place).