advice on cloning laptops to NAS box

Afternoon chaps and chap-esses :)

We are just in reciept of a lovely QNAP 4 bay NAS with 8tb drives in a RAID 5. I wish in future to clone teachers laptops over the network and store the images on it.
I am looking for a nice easy open source program with a GUI to do it, i've looked at some as soon as I see terminal windows and shells I just freak out lol.

Can anyone recommend a program which possibly could run on a portable USB and have a link to to the download :)

Thankingyouverymuch :)