I apologise in advance if the question of this sort is not appropriate for this site.
I am new to SageMath and have been exploring computations related to elliptic curves with it, this hasn't been a difficult thing to do as you have to just copy the commands from the internet. But a few days ago, I came across this : https://arxiv.org/abs/1812.10415
On page 68 here, the author has done some computations using SageMath and got things like blinds on the rank of quotients $E(\mathbb{Q})/\hat{\phi}(E'(\mathbb{Q}))$, $E(\mathbb{Q})/2E(\mathbb{Q})$, Selmer groups, etc.
My question is, how do I do the same? I am familiar with the two_descent but it only tells you whether two-descent can be done for an elliptic curve or not and certainly is not as elaborative as the one used by the author in this pdf.
I haven't been able to find any manuals online either that begin to explain this, plus I don't know anyone in real life who's familiar with it. So I'd appreciate it if someone here could help me out.
Thank you so much.