en_tn/act/08/29.md

Do you understand what you are reading?

Can be translated as, "Do you understand the meaning of what you are reading?" The Ethiopian could read and was intelligent. This was an issue of spiritual understanding.

"How can I, unless someone guides me?"

This is a rhetorical question for "I can not unless someone guides me." It is used to emphatically stress that he could not understand. (See: rc://en/ta/man/translate/figs-rquestion.)

He begged Philip to…sit with him.

Also implied, Philip agreed to traveled down the road with him. (See: rc://en/ta/man/translate/figs-explicit)