If you want to conduct auto repairs to your Suzuki GS 400 E then it will always be a good idea to have access to a Workshop Manual to use as personal reference if you want to know the best ways to strip off a specific part such as the Door and fit it again appropriately.
Suzuki GS 400 E Workshop Manuals provide you with detailed diagnostic details on your car so if something is wrong it will help you work out what the problem is and the best way to fix it. After that you can determine if this can be done on your own or in the event the job is simply too big you are able to make a reservation for your GS 400 E into a trusted mechanic.
Suzuki GS 400 E manual