Hi! I want to create a sewing pattern on Ribblr, and I was wondering if it’s okay to include a printable pattern template and then provide written instructions on how to sew the pieces together.
Yes, I think it would be necessary to provide a printable pattern template and then provide the written instructions to detail the assembly/sewing process. 
Thank you
that sounds like you can do that also if @IMadeIt 's post helped you might wanna mark it as the solution!
Perhaps also check out what other sewing pattern designers are doing to get some further insight.