How did king David consult with God with an Ephod (stones) ?

Can our Christians friends tell us, how did King David and Aaron consult with God through stones?

9 When David learned that Saul was plotting against him, he said to Abiathar the priest, “Bring the ephod.” 10 David said, “Lord, God of Israel, your servant has heard definitely that Saul plans to come to Keilah and destroy the town on account of me. (1 Samuel 23:9-10)

How did king David consult with God with an Ephod ? The Bible tells us the Ephod was a linen clothing, attached with a breastplate with stones on them worn by the Jewish high priest.

The Biblical description (Exodus 28:16, 39:9) continues describing the size of the breastplate which is affixed to the front of the ephod as a square measuring one span by one span (the width of an outstretched hand from little finger tip to out stretched thumb tip). Stating that it was held together by a girdle, and had two shoulder straps which were fastened to the front of the ephod by golden rings, to which the breastplate was attached by golden chains (Exodus 28:6-14). From this description it appears to have been something like an apron or skirt with braces,

The integration of the stones in the breastplate, as well as the Hebrew usage of "Urim" as "lights," suggest that the Urim and Thummim may have been a type of ocular device through which the priest would look when receiving divine communication. (Encyclopedia Biblica. 1899.)

According to the Talmud, the wearing of the ephod atoned for the sin of idolatry on the part of the Children of Israel. (Babylonian Talmud, Zevachim 88:B)

even Aaron used stones to communicate with God

Aaron would place two "stones" near his breast (Urim And The Thummim) when entering the the lords holy place

Also put the Urim and the Thummim in the breastpiece, so they may be over Aaron's heart whenever he enters the presence of the LORD. Thus Aaron will always bear the means of making decisions for the Israelites over his heart before the LORD. (Exodus 28:30)