Find a hotel and book a ticket on a boat down the Li River, which will leave early in the morning. There are about a dozen shops that rent bicycles and they have signs in English. Bike around town a bit. A trip out to the Reed Flute cave is a very pleasant excursion. Take your bikes onto the boat and enjoy a scenic cruise down the river, arriving in Yangshuo in the afternoon.
Lunch is served on the boat.
Most of the other tourists will probably be Chinese and the guide will be speaking Chinese, but the sights are enough. Yangshuo is a crowded place for about two hours until all the tourists pile onto buses for the trip back to Guilin. It is not possible to do this trip the other direction since the boats do not carry passengers for the return to Guilin. After they leave, Yangshuo is a very relaxed and pleasant town. It is one of the smallest towns in China open to tourists.