Sure, but if it's an existing walkthrough, can you tell me which one it is?
here is the link, but if it doesn't work then here is how to get to it:
http://www.gamefaqs.com/portable/ds/file/943695/56036
1. search Fire Emblem Shadow Dragon at gamefaqs.com
2. click on faqs
3. it's the walkthrough by LethalRedArmy