basically the same as any other toning process. Decide what you want to use. Take a print, pre-wet. place in the solution, l.e. coffe, tea, etc. pull and wash.
there is some debate about tea being somewhat archival due to the tannic acid in tea. Don't know about food coloring or coffee, but have my doubts.
the type of tea ; i.e fruit etc will effect the tone of the print . Most who try this use a strong black tea rather than a light fruity tea. Never tried the others so i can't comment.
We tried tea in my basic toning class and it won a "thumbs down" vote from everyone; so now we don't take the time with it, however, that is not to say there will be others who think it is grand.
there are so many other stable photo toners that it didn't make sense to us, as the results where quite ugly.
However, get it a go and decide for yourself.