need help I screwed my macbook so bad thiere is one drive and no partitions, please read below
This is a duplicate of many questions where you boot to Recovery and re-partition / re-download an installer and set up a new OS. 


https://support.apple.com/en-us/HT201314


You can bring another bootable volume to the Mac as well or bring a bootable installer or just a drive with a local recovery partition as well. You don't have to erase anything - main thing is to get another OS running so you can decide if you need to backup or do data recovery. If you have a full backup or can walk away from all the data - just erase the volume and set up a new OS.


Can&#39;t start Mac in recovery mode - only get folder with question mark instead