If I were just starting the thing of steelhead flies, I would start with a couple simple patterns that use simple (cheap) materials that appeal to you. My first steelhead (a winter) and a number of others came on a simple yarn fly some 60 years ago. Like many in the steelhead came over the next 10 or 15 years the search for that magical fly that would consistently produce steelhead for me. Some time in my second decade I learned some lessons that I now pass on to those beginning down the path of chasing steelhead with flies.
Those lessons are there are 4 major factors in success in your chosen game of catching steelhead on a fly. One of course is that magical fly, second is an understanding of steelhead, their life histories, how they migrate, what sort of water they use, etc. The third is how your chosen river(s) accommodate the steelhead and their needs while in the river. The fourth is how to present your fly to the fish and what presentations are most successful. Of the 4 aspects of this steelhead game IMHO the fly used is by far the less important. Most any fly that you have confidence in will produce fish - just keep them wet!
The other 3 are the most difficult but fortunately there is a lot of information that one can read and discuss with fellow anglers. "Book learning" will get one well down the road of understanding the fish. The presentation piece has information available. In addition to supplement that presentation piece I would spend some time fishing with a dry line and an unweighted fly. This allows for a two-dimensional presentation that is readily visible to the angler. Spend time watching your fly noting how it swims at various angles, how the fly responds to various mends. Once you understand how the fly is presented on the dry line you are ready to move on to the sinking line trying to visualize how your fly is swim based on what you learned with the floating line.
The final and most difficult piece is learning how the fish use the various types of water. Basically, you are trying to predict to predict where the fish will be. Bottom line typically we find roughly 90% of the fish will be in (either traveling or holding) in 10% of the river. Your goal is to learn enough to be able to spend 90% of your time fishing that 10% of the water. Our very best steelheaders have perfected this ability to a point where they can confidently walk into a new or changed piece of water selected that high percentage water. Those that have gear fish have a step up in that learning process only in that they are likely to encounter more fish (getting feedback). Once one understands where the fish maybe that the final step is learn which of those locations (and when) are best suited to your chosen method of attack.
A final comment with the lower abundance of steelhead on most waters today it just takes longer to amass enough encounters to get the needed feedback to refine your game. Have fun with this whole process in one of the most challenging and most rewarding of many of us consider the ultimate in fly fishing.
Curt