This is the 16922nd most frequent Russian word.
солдатом
"Солдатом" means "as a soldier" or "being a soldier."
In this sentence, "солдатом" is in the instrumental case, showing the role or profession someone aspires to.
Он мечтает стать солдатом.
He dreams of becoming a soldier.
Here, "солдатом" is used in the instrumental case to signify the state or condition adopted by the individual.
После окончания академии он стал солдатом.
After graduating from the academy, he became a soldier.
In this example, "солдатом" is instrumental, describing the capacity or role during which experiences were gathered.