Dear just purchase Dogar's ISSB book. There is A-Z complete detail of ISSB. Only some tips i want to add here
1. Be yourself
2. Confident
3. Helping hand, supportive
4. Dont lie
5. Good communication skill and general knowledge
6. good reason to join forces
7. Leadership qualities.

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"The sound of laughter has always seemed to me the most civilized music in the universe."