Roundabouts unsettle a lot of learners. The key is to decide early: the right lane, the right signal, and the right moment to go.
Use the road markings and signs on approach. As a rule, take the left lane to go left or straight ahead, and the right lane to go right or full circle, unless markings tell you otherwise.
Deciding early means you are not changing lanes at the last second, which is where mistakes happen.
Signal right if you are going past twelve o’clock, and signal left as you pass the exit before yours. Look to your right, judge the gap, and go when it is safe.
If in doubt, wait. A short pause for a clear gap is always safer than forcing your way on.