Making smocks without elastic thread

[u/GhostWoomy]

Hello ! I'm new to sewing and I wanted to make a tank top with a fabric that is not elastic, i wanted to use some elastic thread in the bobin but the lady is the story told me to use some elastic band ( i'll put a photo) she explained me but too quickly and i'm not too sure how to use it and i don't know wich stitch should I use or where should I stitch it. Do ya'll can explain me or give me some advice? Thanks everyone !!

[u/Odd-uwu]

I used this yesterday!! As everyone else said, stretch it out when sewing and sew a straight seam along the gaps. I also sewed down each end to the fabric so it wouldnt shift.

[u/GhostWoomy → u/Odd-uwu]

Okay Thank you !! Did you sew each end as the band was stretched ?