Narrative Auctions work similar to eBay. The minimum/opening bid is found on the Niche card. This initial bid is displayed in NRVE but equates to USD$75. The initial NRVE bid goes up and down as it is synchronized with the value of NRVE on CoinMarketCap. This is why the opening bid may fluctuate.
Similar to other online auctions, when you create a max bid that is more than the current bid it will always default to the next value. For example, if the opening bid is 10,002 NRVE, you can put a bid in at 10,002. If another person places a bid at 10,003 you will not be the highest bidder. If you put your max bid in at 10,300 NRVE, the system will indicate that you have an opening bid at 10,002. However, in this case, if the next bidder posts a bid at 10,003, they would temporarily have a leading bid until the system automatically outbids them with your next highest bid, which would be 10,004 since you have a max bid greater than the new bid. You will get emails to confirm that your bid is highest or whether you have been outbid. Remember multiple people can post higher max bids, so it is not unusual to see many automated bids happen.
Auctions run for 72 hours. If you win the auction, an email will be sent with directions on how to pay for the Niche. You can choose to use a credit card or NRVE to pay for your Niche. See this FAQ for more help on paying for your niche.