Welcome to Flyertalk and welcome to the BA forum
tilal6991. It's good to see you here and I hope we will see more of you.
{edit: rest is just a repeat of what KARFA has posted}
If you have a look at the main thread here, you will find towards the end references to BA's Trade Support guide for longhaul Basic fares. From my reading of it, I don't think you get seat selection on AA metal however you do it, since normally we have use AA's Apps (etc) to select seating, but it's out of my field of competence so I'm not certain. On BA metal as a Silver you definitely get seat selection and you definitely don't get a bag.
https://www.flyertalk.com/forum/brit...announced.html