Yep, as Dan says, you need a real supplier of real screen printing supplies.
Where did you get your emulsion? Is that the Speedball also? (if so, it's Diazo Sensitized stuff and does not benefit from the post exposing you asked about previously)
That said, even Speedball has instructions as well as instructional videos on their site
https://www.speedballart.com/our-product-lines/speedball-printmaking/speedball-screen-printing/speedball-screen-printing-inks/speedball-fabric-screen-printing-inks/They do bring up the issue of printing on darks, that require their specific line of Opaque inks.
Now, back to the supply issue. Though we welcome newbies, and today's hobbyists may well become tomorrow's large voluime shop owners, this forum pretty much is populated by folks doing this commercially. Hence, commercial level supplies are usually discussed. Though with the internet, one doesn't need to be limited specific brands and to local suppliers, but I do know of at least CMO in Quinton.
Now, back to basics, often, the first line of inquiry about technical issues with a specific product can be handled by the techs at the specific manufacturer. I know that Speedball takes technical inquiries via email, but perhaps their customer service phone can also direct you to them. 800-898-7224
Oh yeah, and even more basic, is to get and read the instructions on these products, LOL!