Where to buy tent port sleeves with draw strings?

I'm a DIYer, and I'm building a tent. Where can I acquire those port sleeves for ventilation/wiring with the draw strings?

Take a square piece of cloth, roll it into a tube.... sew the seam.... then sew/fasten the edges of one tube end to your tent material... tada... sleeve...

For the drawstring, before rolling into a tube, on one end fold the edge over a string allow each end to come out a bit at the "seam" you would create above... tada... drawstring!

You could use other things to make ports into your tent like PVC pipe/fitting.... that's another avenue you could consider...

Thanks for the reply, I have no experience with sewing, and I'm unsure how to attach the "tube" to the tent at a 90 degree angle. Was hoping someone sells pre made accessories that I could tap on.

I'm also not convinced black and white poly is the best material for sewing...could be wrong. How would I use pvc, and have it light tight?

I think there is somewhere online that sells the actual tent fabric... an eBay store IIRC...

Otherwise you could get real creative and use something like a tarp and somehow attach (glue? sew?) the White poly to it so it's a super strong material and yet reflective... But I imagine the cost of the materials and effort wouldn't be as wise of a choice as finding a source to just buy the shit... I know I stumbled across somewhere once... If I find it I'll post a link...

i saw that tent material somewhere, but it was like $160 for a roll. i would try some old canvas chest waders or something similar, it doesnt need to be reflective. as far as sewing goes, search youtube for sewing videos

Use something like THIS and just attach an elbow or ducting to it.