I hope you can help me resolve my problem of setting up my Dual Boot with Windows and ubuntu.

I followed this tutorial specifically : https://www.youtube.com/watch?v=ZP3o_hw1eYI

once arrived on the disk configuration, I chose the manual partitioning where I select my desired disk space I can not do next, the next button is disabled…

I can’t find a solution to that if you have any leads to explore, they are welcome

I tried to repartitione my disk but it tells me that it will format my disk what I do not want…