Please, don't put it all in the imp or all or rep or cis folders. We've already got all the assets aside from what you add, so it's just wasting space. It's best to create a new side. Either 1 whole side for every new vehicle or unit you're adding or a new side for each individual one. It makes uploading and downloading much faster, as well.

For information on how to create a new side, visit Saturn_V's website (link is in the left toolbar) and look at his tutorials.

Or in BFBuilder Pro you can choose Create new side. Or you can do Import retail side and choose SNW(empty folder) or one of the locals.