you have to proceed very systematically and with caution. She must have been symptomatic. Has she seen a physical therapist. If yes, that would be your first line of inquiry.
If no, I would start with isometric exercises and have her learn to hold a neutral pelvis and then move on to very small movements like pelvic tilts. The next thing is to find what irritates the lower back. Moving into flexion and extension, she should tell you where her threshold is. Then you have the low back exercise stand-by exercises like bird dog, core movements on her back. When I have a client with a history of lower back problems, I stay away from any unsupported forward flexion.
It is really a constant dialogue between you and your client to find the best path.
The site and position of the bulging material is very important in this situation. As well as medical clearance and recommendations/contraindications. In general static stabilization will be the mainstay of this type of program design. This will no doubt be a very good learning opportunity for you. I recommend you thoroughly research this topic as well and/or find someone to mentor you on this in person. Be cautious, but remember experience is a hands on part of learning.
I would also recommend regular icing of the location post exercise as well as a high quality warm-up to limit any discomfort during the exercises explained above.
Your routine should roughly be:
-Warm-up (5-10 minutes of light cardio either on a bike or walking depending on what is most comfortable for client)
-Stretching of back and lower body muscles (piriformis, QL, ITB, hamstrings, quads, calves, and thoracic region) within comfort zone.
-Mobilization exercises (pelvic tilt, bird dog, cat and camel) progressing in difficulty as exercises become easier.
-Ice (Ice is a natural anti-inflammatory agent and it tends to cool off the muscles, which is why you wait until the end)