@AO Thank you for reaching out to us, As I understand you are planning to migrate/move from a non-Microsoft endpoint protection solution to Microsoft Defender for Endpoint.
Would recommend to review this doc - https://learn.microsoft.com/en-us/defender-endpoint/switch-to-mde-overview which has the detailed steps, process of migrating to Defender for Endpoint can be achieved in three phases as mentioned in this doc.
Reference:
https://learn.microsoft.com/en-us/defender-endpoint/migration-guides
https://techcommunity.microsoft.com/t5/microsoft-defender-for-endpoint/bd-p/MicrosoftDefenderATP
For license details - https://learn.microsoft.com/en-us/defender-endpoint/minimum-requirements
Above mentioned doc should be the best guide to begin with, if in case you have further questions would recommend engaging our consulting team who can assist you further on this.
Also, came across this youtube video - https://www.youtube.com/watch?v=_MiNDetIAvk which might help here.
Let me know if you have further questions, feel free to post back.
Please remember to "Accept Answer" if answer helped, so that others in the community facing similar issues can easily find the solution.