"How do you get flood icing from the bowl into the squeeze bottles?"
Here's my secret...I don't have a secret. I just pour it in.
Take an empty squeeze bottle,
and icing thinned for flooding,
preferably, do not try to do this while holding a camera in one hand.
Pour in s-l-o-w-l-y.
There we go; that's better.
I'm right-handed, so normally, I hold the container of icing in my left hand and with a silicone spatula in my right, carefully guide the icing into the bottle.
{Sometimes it gets messy, but usually I can make it with no spills.}
If it does plop over the side, wipe it up with a damp paper towel.
There it is...my non-secret secret.
I guessing someone has a better (neater) way. Spill it, sister (not literally).