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The instructions to move issues from backlog to the active board view will depend if you are using a Kanban or a Scrum board.
Also, in JIRA Cloud we have both Next-gen and Classic projects. Can you let us know which one you are using?
Supposing you are using a Classic board:
1 - If you are using a Kanban Board, the differentiation between the backlog and board issues is the status.
That being said, you must Navigate to your board > click on the three dots at the top-right corner > Board Settings. Then, navigate to the column tab and check which are the statuses mapped to your board columns - that are not in the backlog.
Once you know this, you just need to move your issues to any status in the board columns to properly add it to the board view, optionally using the Bulk operation functionality.
2 - if you are using a scrum board, the differentiation between the backlog and board issues is that the board issues are added to a Sprint.
With that in mind, you must create a Sprint in your board. Once do it, add all the issues you want to the Sprint (Using the Bulk operation to change the Sprint field value) and start the Sprint.
Supposing you are using a Next-gen board:
1 - For Kanban, you can only map issues manually in the board view.
2 - For Scrum (Sprints), you can use the same method as the classic projects to achieve the bulk operation.
let me know if you have any questions.
Bad luck on this, I'm on this case:
1 - For Kanban, you can only manually map issues manually in the board view.
Also there is a typo on your answer: the second bold statement repeats the first, I think it was supposed to be "Supposing you are using a next-gen board:" instead.
Thank you for your feedback.
Additionally, if you really need the ability to bulk move issues from backlog to a Next-gen Kanban board, I Suggest you two possible workarounds:
1 - Navigate to the project settings > Features > Turn-on Sprints for your project.
2 - Follow the guide below to migrate your next-gen project issues to a Classic project:
Have a nice day!
Simple workaround, originally provided by Aliya in this thread:
Just disable backlog and all issues will be moved to the board.
Then simply enable the backlog once again.
P.S.: If anyone will have issues with "Done" column not showing "Clear issues" (in our case it was due to imported project), just use Bulk edit option and use "Transition Issues" option to move them to "Done". Then "Clear issues" option will appear.