Ah.....
The HDD is 1T but m.2 is only 240gb so meaning cannot?
Sent from Xiaomi MI MAX 2 using GAGT
Am assuming your laptop m.2 is SSD type as m.2 has SSD format or newer type is NVMe type.
Next I assumed you will keep your 1TB disk as data and m.2 become a boot drive.
1. Move all your data out to USB drive and ensure you use only less then 200G of data on your disk.
2. Use special clone program to move OS from HD to m.2
3. Boot OS from m.2 and confirm it is working
4. Format your 1TB disk and move back your data to 1TB disk from USB drive.
Not sure your notebook happen to be Thinkpad. I did that before. Boot OS on 120G m.2 SSD and data on original 512G disk. Newer Thinkpad should be NVMe m.2 already.