His heart was lifted up means Ptolemy “became too ambitious” (Good News Bible). He thought he was greater than he was and wanted more than he had.

He determined to get control of the country: The country refers to Judea, the land ruled by his father-in-law Simon. This clause may be rendered “He wanted to rule Judea.”

And made treacherous plans against Simon and his sons, to do away with them may be expressed as “so he devised a plan to murder Simon and his sons.”

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.