Hello, i'm new to this site too. I recommend you the book "el verdadero bajo cubano" (The true Cuban Bass) by Carlos del Puerto & Silvio Vergara. It guides you thru History, Concepts of the clave & different styles of afro-cuban bass. It's a very good book in every aspect, because it takes you from the begginings of that style of music, has chart music of different styles, and gives you very useful examples for improvisation on the basslines. I would say (it depends) that on afro cuban styles generally you have the chords & improvise, except on obligatto parts... In the book there are examples of obligatto basslines too... Same thing happens on Tango music (has his early relationship with afro-cuban music, habaneras) , you have more orchestal tunes with written parts, & you have other tunes in which you can improvise the bassline... I recommend to write the harmony & times using guitar or piano & then improvising thru them, because sometimes i'ts difficult to get the charts, i think it can be a more direct approach time-wise for you... I hope you encounter this useful.