River Crossings for Dummies..help pls

[Demtrek]

Ive done a search and I read the spots in the manual which refered to amphibious assaults, however in the maunual it shows all ocean where the barges start out.

On river crossings I get all my stuff loaded into the barges but the grey start line prevents me from placing the barges in the river. I see I cant move them on my own either.

What am I doing wrong? Do I need big trucks to carry the barges to the rivers edge?