whats the easiest and cheapest way to travel from paris, france to italy and back in a few days?

im in paris current as of the 28th and i wanted to travel visit italy and maybe spain via the train. i was trying to figure out exactly what i should be looking for and/or what is the easiest and cheapest way to go?

What is the cheapest way to travel from Paris to Italy and from Paris to Spain?

If I were looking to travel from Paris around Europe. How long does it usually take to get from Paris to Spain or Italy? Thanks everyone!