Hey there , I have already completed over 100 video-editing projects on different platforms, most of them were short ads like the ones you are asking for ( 15-30-45 ) sec. I can help either if you had footage or not, as I have tons on stock footage and music and I will find my way to make perfect ads, also with my experience I know the publishing rules for Instagram and Facebook, so you will fae no problems at all
Please contact me so I can show you some of the previous work and to talk about details, I will be waiting for your response <