I am no pro myself, but I would do this:
Use the campaign with the video and run it good.
– figure out at what point the message in your video get clear. I mean, at what % of your video, the audience will get your idea clearly. For example, 75% of it.
– build a custom audience based on those singulars that’s saw 75% of your video.
-Show them (!) one single post ad, targeting conversions, with the offer you talked about (700 to 100 in the beginning). Cta and offer will get them to your page.
So, then you wait. Increase the base audience, do a Look-alike of that audiece (saw 75% of your video) , somewhere around the 2 or 3 %.
Use it on the 1st video, to build better audience.
Make a rmkting campaign for those who walked on your grounds.
This is the base that I would use, of course I don’t know exactly all details of your business.
But, you know, run tests and stuff 😀