The New Singer Futura range, eg, CE150, CE200, CE250, CE350 uses .FHE embroidery format and also CHE (Compucon) design format - however the Singer software that comes as standard with many Singer Futura will automatically convert the following embroidery formats,
XXX
PSW
PEC
PES
HUS
SEW
EXP
DST
PCS, FHE and CHE, purchase any of the above formats is fine.
However Singer's most usable format is .XXX
Singer XL5000 and XL6000 use the format with the file extension .XXX
Singer's software called "Singer PSW" a hardware and digitizing software package will load and save in many different formats but buying .XXX you'll be safe.
Older machines like the Singer Quantum XL-100, XL-150, XL-1000 use .XXX format
Best option to learn might be you tube.com There are plenty of videos on the Futura embroidery features. I taught myself with the manual doing the examples and or doing research on a specific feature when I wanted to do something. Forgot to mention I own a Brother ULT and the PEDesign software.