The guilds module is more advanced than this simple form, but the rest is handled in the game, like privileges management. Changing message of the day, promoting, demoting, inviting to the guild, and more.
In this form you are defining guild levels, requirements per level, and changes that these levels will apply for the guild.
Level: Defines guild level
Members Number: Deines maximum number of members the guild can have on the specified level
Merchant table: Defines merchant table to which guild members will have access using dialogues when the guild level will be reached.
Warehouse number slots: Defines the number of slots the guild will have when the guild level will be reached.
Item: Defines the item in combination with the count that will be required to increase this guild on the specified level.
Count: Defines the number of items that will be required to increase this guild on the specified level.