First a small quantity of the chemical is taken. To this sample few drops of concentrated hydrochloric acid are added.

Now a clean platinum wire is dipped into the mixture and put into a hot Bunsen flame. A platinum wire is used as it is very unreactive and will not react with the chemical.

The color of the flame will change according to the type of positive ion present.

I hope this helped you. If you have any questions please comment and I will try to answer.