I would strongly agree with patcooke's recommendations regarding imaging software and I am also a huge fan of Acronis True Image and have been using it for years, without any disappointments or real problem issues, it's saved me untold hours over the years and can't say enough good things about it.
However since your initial question involved a product called CloneZilla (something I haven't yet tried) I'll refer you to a thread in this forum created by member fjgold in which he provides a link to a tutorial he created which specifically addresses a step by step process using that product. I'm not sure how dated it might be regarding the version he uses but I suspect that the underlying procedures should still be accurate.
Link...