First and foremost, you must join a Guild; the more active the Guild, the better. Then you'll be able to participate in Guild events. Following Guild events such as the Dragonboat Race, the Auction House will open. The more actively you participate in Guild events, the more items will appear in the Auction House.

Auction House Guide
After the Guild events end, the system will automatically distribute rewards to the Auction House based on the performance of each Guild in the event. Every item has a starting bid and a buyout price. The bid price will continue to rise as the players bid, but it will never exceed the buyout price.
The Guild Auction House will launch first, and your opponents will be players from other Guilds. Here, it's recommended that the Guild Leader make some rules to ensure that everyone can get the item they want while expending a minimum number of meteorgems.
If an item has not been auctioned off in the Guild Auction House, the system will transfer it to the World Auction House, where it will be available for bidding by any player on the server. the competition has reached a new level at this point, but you don't need to worry about the Guild members' relationships anymore. If necessary, you can simply go for the item you desire.
The following are some suggestions on the Auction House that Guild Leaders may find useful:
1. Start with a low price and let the first bidder take it from there; no one should keep bidding up the price.
2. If it's something you really need, you can pay the buyout price to get it directly (other Guild members will benefit from higher dividends afterward).
3. Set an open auction day that everyone can bid freely on that date, and all other dates must follow the rules.
4. In the event that rare Divine Weapon Jade of Kings is in high demand, the Guild Leader can make a name list and ask the members to take turns buying it at the starting price.
Auction House Bidding Guide
The Auction House contains a variety of items, which you must select based on your own needs. Here is a quick rundown of the items that should be prioritized: Jade of Kings (a very powerful Divine Weapon), Title Tokens, Soul Edicts, and Souls (Buy Souls that you'll need in large quantity first, such as Zhuge Liang, Zhou Yu, Lu Bu, and so on), Satin, and so on.
It is best to start bidding on the above items at the auction's starting price. And you can think about paying the buyout price directly for some high-cost, high-performance items. Anyhow, the ultimate objective is the growth of your squad.