Ahh you want to specialize in just suspended cielings, and probably
small jobs.

while most potential customers will want someone to do say paneling or
other stuff for small jobs.

I have my own business fixing office machines, pia paperwork.

dont forget sales tax even if you dont charge it on your jobs of say
iots tax exempt theres still paperwork to do, the sales tax license
allows you to avoiid paying sales tax on stuff you buy