I agree with Jim, the red is probably a traveler, whites all tied together are probably neutral (check with a meter).
A 3 way setup usually has the power coming into one switch using a black, white, and ground; then heads to the other switch with red, black, white, and ground; and then the other switch would have a black, white, and ground heading to the light.
Which wires did the old light come off of? Ground should be obvious, but of the other two wires you disconnected from the old fixture you should be able to determine which is hot and which is neutral with a meter, then connect black to the hot wire, and white to the neutral.
To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault