The first thing you should learn about three way switches is how they work. Once you know how they work they are so much easier to wire.
All neutrals (usually white) are tied together, which means the light bulb always has a way to return the current to the source (a complete circuit).
The hot (usually black and red) is what is opened or closed by the three way switches.
The main mistake when wiring a 3 way switch is not to tie the common to the power source on switch one and not to tie the lamp black wire to the common on switch two.
Notice that in the position above the lamp will be off. If you move the toggle down on the first switch then the power will be connected all the way through the the black wires to the lamp. If you move the toggle up on the second switch then the power will be connected to the lamp via the red wire. Either switch can then make or break the connection that allows the power to flow through to the lamp.
There are also variations of this configuration when the power is supplied to the lamp first. or if the power is supplied to switch two, but the principle is the same. In both of the later cases you must use the white wire to carry power or the hot leg and is not the preferred method, but is approved by the NEC. Typically, when this is done it is common to place a black piece of tape on the white wire to make you aware that the white wire might be hot. If you need the schematic for these variations, feel free to comment and I will be happy to create them.
I’m happy to help further over the phone at https://www.6ya.com/expert/bob_62dfa2f81bb55288