Yes you should have steps. Depending on how much of a drop you want from your picture you could do 3 to 4 steps. Make sure the sides with liner are at least 6" to 8" high. By the time you add your waterfall rocks that will reduce the water level along the sides by 2 to 3". Make sure the dirt in your steps is well packed and if you have liner underlay lay that before putting down your liner. I used carpet under mine. You could also make pockets along the edges to hold plants like water iris and plant the iris in gravel in the pockets. When you lay flat rocks in the waterfall stream make sure they are level side to side with a slight slope down. When I did mine I started at the bottom and worked up and used smaller rocks to hold the flat rock above it like a lip over the layer below. I know it's a pain but I laid everything out, used a garden hose to check the flow before I started foaming the rocks down. Use black waterfall foam if you can afford it to hold the rocks in place and to keep the waterfall water going over the rocks instead of under. Great stuff low expanding window foam works great but is an ugly yellow color. After it's partially set you can throw sand against it to hide the foam. Wear gloves as it sticks to everything and is impossible to get off your skin. The foam needs a day to set before running the waterfall. You probably have the black silicone for your liner attachment to your waterfall basin. Don't forget to leave a loose section where you attach liner to the waterfall thing as the weight of the rocks will pull the liner down. Hope this helps. If you do a search for waterfalls on this site there are some great pictures. Patti

I have an extra word of advise on top of what Patti said.

Wear TWO sets of rubber gloves!!! As one gets all gooked up with the foam you can take that off and have another pair already on your hands. I learned this from experience :-)

Anne

Thanks so much for the advice. We didn't step the slope so I am sure that tidbit will help greatly. I had a landscaping man come and look at it and he wanted $400 to fix it. No way do I have that kind of money so I will try using your suggestions.

There are a number of sites on line and even some youtube videos that have info on building your own stream. A google search of diy pond stream will give you a bunch of options. One I like that has some clear pictures of the after part is shown below.

Good Luck. IMHO Streams are almost the best part of a water garden.
Anne

Here is a link that might be useful: DIY Stream