OK we had a really old bladder tankin my well house. So old that it blew some holes in the side of the tank. It's a horizontal tank. And this guy came over and replaced it with a vertical tank. The tanks are so different. There's no place of a pressure gauge to go and the pump won't stay primed. Sorry for the little info but usely I figured this stuff out on my own but we have not had any water in like 4 days going on 5 so any help would be great. Or maybe I'll just go buy and new horizontal tank and just put it in myslef

There are two types of pressure tanks. Which one did you have and what was replaced? (see images) Describe your old tank. What color was it?
Most bladder tanks mount in the upright position. Any of these look familiar?
If you prime the pump and the water runs back out then I would be giving the check/foot valve a good hard look. Good luck, Tom