Not being condescending, but just open the hood and take a look see.
You can buy an adapter to convert a side post to top post or visa versa.
You can buy and adaptor to connect the top post cables to a side post battery. Or you can simply replace the side post cables with top post cables.
Top
Top Post
Top
It is as simple as changing the battery cables.
Top post.
It is a side post.
Top
Battery size should be listed in a catalogue where you buy it. That's a top POST battery , terminals are a standard size, one is larger than the other, are you sure you are not trying to hook up bacwards - NOT A GOOD THING!
The post with the red cable attached to it. The positive post is slightly larger than the negative post. + & - is normally printed on the top of the battery next to the post.