No problem...
There should be a hole in the firewall that already has a 3/8" headed screw in it. There might even be a few of them... Now, you won't be able to see the hole, of course, as the bolt head will be all you will see.
The bellhousing is the front most part of the transmission that bolts to the engine... If you were to take it off and turn the front side down, it would look like a bell. If you strike it with a wrench while it is facing down, it would sound like a bell...
Here is a good pic of one:
The ground strap should be connected to one of the bolts that runs through this bellhousing to the engine. It will be on the passenger side at about 10 o'clock facing the front of the vehicle...