As title, I'd like to know what to do when conducting an ensemble group such as quintet, I couldn't manage to sum things up as maybe I've been to hard on myself to make things perfect. And DO and DON'ts?

With a small group, like a quintet, I'd direct from an instrument rather than 'out the front'. Give a good clear lead (particularly at the start, the end and at cadence points), otherwise, have a good play and enjoy!