I want to receive some help to understand Instance and array in the following context:
UKBB: The standard dataset (downloadable directly by researchers) contains a record of all the bulk data-files approved, however only the data-file IDs are present rather than the actual contents of the files themselves. These data-file IDs have the format "F_I_A" where F is the field ID, I is the instance index and A is the array index. Hence 8034_4_2 corresponds to
Field 8034, Instance 4, Array 2.