After a short time; in a little while. A set expression indicating that something happens shortly afterward.
しばらくすると雨が小降りになった。
After a short while, the rain eased up.
駅で待っていると、しばらくすると友達がやって来た。
I waited at the station, and after a short time my friend arrived.
説明を始めてからしばらくすると、質問が出始めた。
A short time after starting the explanation, questions began to come up.