Hi bamamelena,
Welcome to Auctiva. You are going to have a great experience.
First, I would highly recommend that you go to your Auctiva home page, click on Help at the very top of the page.
Then select Classes & Tutorials. There is a Video-Audio available for each of the modules:
Listings
Profiles
Images
Auctiva Checkout
Auctiva Shipping Insurance
It will take a little while, not long, to watch and listen to each of the tutorials. This will give you basic info on how to prepare and list.
After watching the videos, I personally, would begin with setting up everything in My Account as I would want. Then prepare ALL my Profiles. After that I would upload ALL my images. Then I would prepare my listings.
Personally, I DO have the Insurance checked, but you will be able to understand more when you view the video.
eBay will always charge you for Gallery, but with Auctiva you can have up to 16 pic's at NO additional charge. The Auctiva Scrolling Gallery has no charge.
This doesn't answer all of your questions, but when you view the tutorials you will have many of them answered for you.
Keep coming back here, use the Go tab and do searches. Probably most of your questions will have already been dealt with.
Good luck and have a great time......