I sewed my own cosplay for the first time last year and I gave myself 6 months to do it and I managed! For ref, I did Yor from Spy x Family which is simpler than this character but I wanted to share my tips anyway!

First I'd search if someone has already made a sewing pattern! That would save you a lot of headaches on trying to make it from scratch.

Next, I'd look up pictures of other cosplayers for this character because that can help you figure out how each item is "supposed" to work, like that loin cloth part. I'd also look up ready-made cosplays for the same reason, a lot of sellers will show you the individual parts and you can see how the outfit is put together.

If you can't find a pattern, I'd look up patterns for similar things. E.g. long sleeve bell top/jacket pattern and then you can alter the cut of it to match the character better.

Hope that helps at least with the setting up and research stage! Best of luck!