To part out a set, go to Want > Part out, and input the set number or choose it by selecting Choose set. A number of options are available here such as including minifigures and instructions, as well as adding the parts to an existing or new wanted list. It is recommended to make sure the checkbox Match Min Wanted Qty with Quantity found in Item it checked so that the required quantity will be added to the parts. Default remarks will set that remark for each item — this is particularly useful if you want to add the parts to a list which already has parts in it. Choose Submit for Edit to move onto the next step.
The next step allows for changing quantities, deleting parts you don’t want to add, and adding remarks to specific parts. Once you’re happy, press Add to Wanted List; the items will now be added to your wanted list.
Next: How to buy parts from a wanted list