I read some about y'all buying the PSA Freedom kits and build your own gun so I went out there looking around and order the complete up right thing and then ordered a lower kit but I'm wondering if I might have forgot to order something I have an a Bushmaster AR-15 that I've had for about 9 years old and really do love it but I want to build this new land with a 1 in 7 twist in a 20 inch barrel

Are you saying that you ordered the upper and lower?  Or are you saying you only ordered the lower?  Are you looking for a 20" upper?  Or are you just looking for a barrel now?

I ordered a 20 in barely w 1 in seven twist.it was 299.00 and said it already had bolt and carrier.pic showed a complete upper.where I messed up was I didn't come here before I order it.as you can tell I am a rookie.i ordered a lower kit because it half of a complete one.but I don't think I ordered right .I was wanting the barrel for some range and accuracy.

Check your receipt.  The only 20" barrel I see on their website is a heavy stainless barrel.  The 20" freedom upper is a complete upper, and costs $299.

Yes that is the one that I ordered but I ordered a lower kit thinking that that was all I needed for the lower but I think I'm going to need what is it a stripped lower to put that in I don't know if I can cancel my order part of it because I think it had already shipped

So go buy a stripped lower.

As just said, get a stripped lower.
Does your lower parts kit come with the trigger? If not, you'll need that obviously.
What about a stock and buffer tube kit?
From the sounds of it, you have to make a complete lower to go with the upper.
20" barrell, I would assume rifle length gas, so make sure your buffer tube kit matches.
Lowers are fairly simple to put together.
do you have a vise, and the block that the stripped lower goes over to prevent damage? Torque wrench and punch kits?

Thanks for all the impetus I have been out of town so that is why I have not been responsive to you comments.my upper was a complete one and I ordered a complete lower after I learned better.hope to get it in this week and will let yell know.