To reset your Samsung T5 SSD, connect it to your Mac and launch Disk Utility (Finder > Applications > Utilities). Select your SSD and click the Erase button. Name your drive, select ExFAT as its format (unless you need APFS or HPFS+ specifically), and GUID Partition Map as its Scheme. NTFS file systems are not compatible with Mac, so avoid it unless you primarily use a Windows PC.