Weapons, armor, and accessories are discussed on the equipment help page.
Scrolls: A scroll is an enchanted piece of parchment that contains the knowledge of an ability. It must first be identified. You can only identify a scroll if your Lore is at least as high as the scroll's level. After a scroll is identified, you can read it to gain its ability. The skill requirements and prerequisites still apply.
Alchemy Items: These items are used to make potions in battle and to enhance weapons and armor at the forge. Each potion or enhancement requires 6 ingredients, some in multiples. The required ingredients for smithing enhancements are listed when you go to smith; the required ingredients for alchemy potions will be listed in the Lucent Ability Research List as ability research progresses.
Selling items: You may sell any item in your inventory. Click on the radio button next to the item you want to sell, then enter the price you want to sell it for. Finally, click on the "Sell" button in the proper list. Your item will be offered for sale in the market of the city that you are currently in.