The guides to the collections will help you to find the documents which are kept in the different departments of the Landesarchiv. They are available on-line. With the help of these guides, finding aids for record groups can be found which are important for your relevant subject.
Finding aids give a short summary of the content of the record, the signature and the inclusive dates. Many finding aids are already available on-line. The button "Findbuch" in the "Beständeübersicht" ("Finding aids" in the "guides") will tell you if it is the case. Besides, every Archives (department) has its own on-line list of finding aids.
Sometimes it is necessary to have a certain knowledge of the administration procedures in order to find the records. If you are at a loss do not hesitate to ask the staff.
The Landesarchiv offers an on-line list of all the finding aids that can be searched.