Ways to define ISMS scope

Here are the answers:

What are the concrete methods and ways to define a good ISMS scope

You need to identify in which part of your company is your most valuable information - see the details here: How to define the ISMS scope https://advisera.com/27001academy/knowledgebase/how-to-define-the-isms-scope/

what steps need to be taken while identifying the risk

Here's the article that will help you: ISO 27001 risk assessment & treatment – 6 basic steps https://advisera.com/27001academy/knowledgebase/iso-27001-risk-assessment-treatment-6-basic-steps/ 

and while writing the policies itself

Here are the articles that will help you: 

• ISO 27001 implementation checklist https://advisera.com/27001academy/knowledgebase/iso-27001-implementation-checklist/ 
• List of mandatory documents required by ISO 27001 (2013 revision) https://advisera.com/27001academy/knowledgebase/list-of-mandatory-documents-required-by-iso-27001-2013-revision/
• Seven steps for implementing policies and procedures https://advisera.com/27001academy/knowledgebase/seven-steps-for-implementing-policies-and-procedures//

These materials will also help you regarding ISO 27001 implementation:
- Book Secure & Simple: A Small-Business Guide to Implementing ISO 27001 On Your
Own https://advisera.com/books/secure-and-simple-a-small-business-guide-to-implementing-iso-27001-on-your-own/
- Free online training ISO 27001 Foundations Course
https://advisera.com/training/iso-27001-foundations-course/