Turn left over the bridge, walk your bike over the glass-bottom bridge and past the museum buildings, and follow the road down the hill and to the right. I had to ask a local for directions as none of this is marked. Then look for the blue paint as seen below -- on bridges, light poles, garbage cans, rest benches, and railings -- and you'll know you're on the trail.
Wet and low areas are bridged as seen below...
Eventually and occasionally you'll get good views of the Tennessee River as you head the seven miles to the Chickamauga Dam (TVA) where the trail ends.
The trail is paved, wide, and in extremely well maintained. This Riverpark greenway is the pride of Chattanooga, is well used, and is well cared for.
Every mile or so you'll come to parks with rest rooms, benches, picnic tables, grass lawns, etc. These are all accessible from Amnicola Road, and if you drive the road and park in one of these parks, you'll have free parking and amenities, and enter the trail at the well-marked segment of the trail.
The Chickamauga Dam signals the end of the Riverwalk Trail.
Tennessee Riverpark website