We have a version 1 dashboard and then developed a version 2. How do we replace version 1 with version 2?

Check these articles. 

• https://help.salesforce.com/articleView?id=home_customize.htm&type=5
• https://help.salesforce.com/articleView?id=000329168&type=1&mode=1
• https://help.salesforce.com/articleView?id=dashboards_embed.htm&type=5