The phrase "under Joshua" means that their ancestors did these things in obedience to Joshua's direction. Alternate translation: "our fathers, in accordance with Joshua's instructions, received the tabernacle and brought it with them"
This sentence tells why the ancestors were able to take possession of the land. Alternate translation: "God forced the nations to leave the land before the face of our fathers"
Here "the face of our fathers" refers to the presence of their ancestors. Possible meanings are 1) "As our ancestors watched, God ... drove them out" or 2) "When our ancestors came, God ... drove them out" (See: [[rc://en/ta/man/jit/figs-metonymy]])
This refers to the people who lived in the land before Israel. Alternate translation: "the people who previously lived here" (See: [[rc://en/ta/man/jit/figs-metonymy]])