en_tn/1sa/02/28.md

to go up to my altar, and to burn incense

This refers to making an offering to Yahweh.

to wear an ephod before me

The words "wear an ephod" are a metonym for the work of the priests who wear the ephod. Alternate translation: "to do what I had commanded the priests to do" (See: rc://en/ta/man/jit/figs-metonymy)