How they were used

Some have proposed the suggestion that the Urim and the Thummim were the 12 stones affixed to the breast piece. That this was not the case is shown by the fact that, in the priestly inauguration ceremony, the completed breast piece with the 12 stones sewn on it, was put upon Aaron, and then the Urim and Thummim were put in it. Some suggest that there may have been a pouch or pocket like section behind the overlapping breast plate in which to put the two stones.

These would be drawn, giving the answer to the question asked, unless the blank piece was drawn, in which case a “no” answer was forthcoming. On one occasion, when Saul had inquired through the priest as to whether to resume an attack on the Philistines, he received no answer (or he didn't receive any answer). Feeling that someone among his men had sinned, he petitioned: “O God of Israel, do give Thummim!” Saul and Jonathan were taken from among those present; after that, lots were cast to decide between the two. In this account the appeal, “Do give Thummim,” seems to be separate from the lot casting, though it may give indication that there was some connection between the two.—1Sa 14:36-42.

Although the Scriptures never describe these objects or their exact method of use, different passages seem to imply that they were employed as lots that would result in either a “yes” answer, a “no” answer, or no answer at all from God. They were for “the judgments of the sons of Israel” and were used when a question of importance to the national leaders and consequently to the nation itself needed an answer from Jehovah. Jehovah, who is Israel’s Lawgiver, would give an answer to the high priest as to the right course to pursue on any matter.—Ex 28:30.

Use of the Urim and the Thummim seems to have ceased in 607 B.C.E. when the Babylonians destroyed Jerusalem.—Ex 28:30; Ne 7:65. According to Jewish tradition, use of the Urim and the Thummim ceased when Jerusalem was desolated and her temple destroyed in 607 B.C.E. by the Babylonian armies under King Nebuchadnezzar. (Babylonian Talmud, Sotah 48b) This view is supported by what we read regarding these objects in the books of Ezra and Nehemiah. There, certain men who were claimants to priestly descent, but who could not find their names in the public register, were told that they could not eat from the most holy things provided for the priesthood until a priest stood up with Urim and Thummim. But there is no record of their use at that time, and thereafter the Bible makes no further reference to these sacred objects.—Ezra 2:61-63; Nehemiah 7:63-65.

So after the Urim and Thummim were discontinued, Jehovah made known his will to Israel by his written Word, also by prophets and by dreams. But it seems that prophets and dreams were used for special occasions, whereas the high priest with the Urim and the Thummim was always present with the people up to 607 B.C.E.

Consulting the Urim and Thummim was said to be permitted for determining territorial boundaries, and was said to be required, in addition to permission from the king or a prophet, if there was an intention to expand Jerusalem or the Temple in Jerusalem; however, these rabbinical sources did question, or at least tried to justify, why Urim and Thummim would be required when a prophet was also present. The classical rabbinical writers argued that the Urim and Thummim were only permitted to be consulted by very prominent figures such as army generals, the most senior of court figures, and kings, and the only questions which could be raised were those which were asked for the benefit of the people as a whole.

Since the priestly source, which textual scholars date to a couple of centuries prior to the captivity, doesn't appear to know what the Urim and Thummim looked like, and there is no mention of the Urim and Thummim in the Deuteronomic history beyond the death of David, scholars suspect that use of them (the Urim and the Thummim) decayed some time before the Babylonian conquest, probably as a result of the growing influence of prophets at that time.

Greater High Priest Consults Jehovah.
Although this section as related to Jesus Christ as the greater High Priest, is in the research I found in the section of the Urim and the Thummim, at this point, I see no connection between the Urim and the Thummim and Jesus Christ, except that before 607 B.C.E. the High Priest then used the Urim and the Thummim to assist in making their decisions in answer to questions and that after 1914 C.E. Jehovah relied on His Son Jesus Christ to represent Him. Somehow, I guess that there is supposed to be a link. So the research continues.

Jesus Christ is described in Paul’s letter to the Hebrews as the great King-Priest according to the manner of Melchizedek. (Hebrews 6:19, 20; 7:1-3) In him kingship and priesthood are combined. His (Jesus) priestly work was foreshadowed by that of the high priest of ancient Israel. (Hebrews 8:3-5; 9:6-12)

Some modern day religions may have claimed use of them in making their decisions, but there is no scriptural proof or even slight evidence to validate their claim. Therefore, it should be concluded that any modern day, or even after the established date of 607 B.C.E. usage is unscriptural and has no Christian or Biblical foundation.