Hi,
You should follow these steps:
1. Select the cartegory (like switches, routers, eNSP, security etc)
2. Select New Post
3. Select "Ask for help" or "Sharing"
4. Create sub-category: In ask for help topic, category is ask for help and in sharing, chose sub-category from tools & Doc, tech exchange, feedback and suggestions
5. Add topic title
6. Create content
7. Submit
This should resolve the issue.