There are two set's I'd recommend highly:
"Immunity" by Alan Belcher.
https://bjjsuperdeals.com/product/immunity-mma-grappling-5-dvd-set-by-alan-belcher/
It shows a lot of good escapes and defences to the common submissions. It's best to not get that far, but if you end up in a bad spot its good to know something to try and get out

And "the blue Belt requitrements"- by Roy dean
https://www.amazon.com/Brazilian-Jitsu-Blue-Belt-Requirements/dp/B001ADKATC
It's a great coverage of the basics.

Hope that helps. Keep training