Some of the best information ever is right at your fingertips in this forum- I refer you to tapla's posts on "Container Soils - Water Movement & Retention."
Link below-

Once you have read and digested that (it won't be quick) then simply browse the forum and read everything that looks relevant. Study. Learn.
A week or two of that and you might be ready to mix up some potting media :)

Here is a link that might be useful: Container Soils - Water Movement and Retention

scouring pad a bad idea IMHO, cearbhaill has given great advice

Thanks for replying, I will definitely keep reading up on it-thanks for
the link. However, ready or not I have already mixed up some potting mix and I'm pretty confident in it. My question is specifically about adding shredded up scouring pads to the mix and I'm still desperate to get some insight into my little green scrubby idea???????

Christine-Thanks for replying, why is a scouring pad a bad idea. I'm not saying your wrong, I would just would like to understand why something is bad, wouldn't work or would.

It might increase drainage or it might trap a bunch of fine material or compress and stay soggy all the time. No one has any idea. So the reason not to use it is that you really don't kow what it will do without further study. There are plenty of materials available that can be used to increase drainage. Use those.

Thanks for replying, others mentioned it might injure the roots, so instead of using it In the soil for my only orange tree I'm gonna use it in a few of the strawberry plants I got coming-just to experiment