SSILD and WILD are similar, though not the same. As for WBTB, SSILD is one of it’s techniques. WBTB itself isn’t a method, but there are many methods that require it. You can find the SSILD tutorial here. I have been using SSILD for three nights now and it increases vividness IMMENSELY. It is also a lot easier than WILD. There are also many success stories from beginner lucid dreamers, which you will just NOT see from WILD.