Bicycle Mechanics - wheel help

good afternoon,
I bought a wheelset online( vento campy 700 clincher ) for a build I am doing, so after setting up the whole bike I start to put tubes and tires on this set , I cant seem to get any tires to fit on these rims,
tried three different brands I had laying around ,I cant even get close to getting them mounted, this is the first time I have ever run into anything like this , any help will be appreciated

how we're they not fitting? tires too big or too small? Maybe the rims you bought were incorrectly sized marked on the box or seller sent the wrong size. You probably got 650's

No tires are right size , just a bear to put on , put them in the dryer and heated them up still tuff fit but finally after three hours I got them on, just hope I dont flat on the road cause I will be screwed
so problem solved for now but I am going to visit LBS on Monday and see what they say

You need to obtain some magical items called tire levers.

Some rims are just a b*tch. I have a Ritchey OCR rim that just about snaps my tire levers every time.

There is also the VAR tire lever that works very well with stubborn tires without ever damaging the rim or tire nor pinching the tube; I've used this for years when I found the Specialized Aramdillos were a pain to put on and broke tire levers. See: http://www.biketoolsetc.com/index.cgi?id=317296144324&d=single&c=Tools&sc=Tire-and-Tube&tc=Tire-Levers&item_id=VR-425

What is the thickness of the rimstrip? Sometimes this can influence the ease with which you can put tyres on rims. If you are using plastic rimstrips, you might consider cloth ones.

Dish soap. Tire lever. Patience. Probably tube patches as well. It just happens some times.