I decided to try selenium toning before fixing my POP.
What is your POP?
I assume you are talking about toning a print.
To selenium tone a print, dev as usual. Make sure the print is fully fixed before toning. Having said that do not over fix the print. If the print is not fully fixed it may stain, if it's over fixed it may not react with the toner.
If it's RC wash for 3 or 4 minutes before toning. If it's fibre, wash for about 20 mins before toning.
Place in toner for required length of time.
Remove print from toner, for RC wash for 3 or 4 minutes, for fibre wash for one hour.
Your stpes should be, dev, stop, fix, wash, tone, final wash.