1 Kings 1:34-35

1 Kings 1:34-35King James Version (KJV)
34 And let Zadok the priest and Nathan the prophet anoint him there king over Israel: and blow ye with the trumpet, and say, God save king Solomon.
35 Then ye shall come up after him, that he may come and sit upon my throne; for he shall be king in my stead: and I have appointed him to be ruler over Israel and over Judah.
American English Bible
34 There, SaDoc the Priest and the Prophet Nathan should anoint him to be the king over IsraEl. Then blow the trumpets and shout, Long live King Solomon! 35 For he will sit on my throne and be the ruler in place of me… I'm giving the order that he will now be the leader over IsraEl and Judah!'

These are my thoughts, please share yours.
34 The Prophet Samuel did this for David. To be anointed as king was to show you were chosen and just not became the king. Many of the kings after this would just become king because of their birthright and not because of being chosen. Solomon was not yet fully made king but was put into this place to avoid and war after David’s death. Solomon was going to be the next king, it was official now.
35 Solomon would be next on throne and be the last king o Israel reigning in Jerusalem after his reign the kingdom divided and kingdom of Israel went north and Solomon’s descendents would be kings of Judah. At this time there was no separation between Israel and Judah but perhaps during the time this was written there was and the note is made to show how strong Solomon’s kingdom truly was.