You'll find it right outside the ticket gates of Sanyo Aboshi Station. This is a Sanyo Electric Railway station, the terminal station of a branch line that branches off from the main line, so it's a dead-end station.
The JR Aboshi Station is located away from the central area, making this station the main hub of Aboshi.
It's 3.5 km away from JR Aboshi Station, and it's risky to assume you can easily transfer just because they share the same name! It takes almost 40 minutes on foot (speaking from experience, haha).
There are only about one or two buses per hour towards JR Aboshi Station.