I don’t know anything about crocheting, but I think your problem may be with the spelling here. I don’t normally correct spelling, and I generally get annoyed when people do so, but in this case searching for “alter cloth crochet pattern” may give you wrong search results.
Try searching for “altar cloth crochet pattern” (with the ‘a’ in altar). I found several thousand pages with that phrase in google just now. I’m afraid I can’t tell you what’s a good pattern, but hopefully this helps.
Saw your question. There appears to be a number of approved patterns. I saw them today but no instructions. Since most of them have a repeated pattern it is probably best to find a motif that matches most closely the pattern you like and go from there. These are really works of art that can be created by the maker with all of the artistic style you can muster.