68 Barracuda ragtop turn signals

Lets diagnose... You must have good dual element 1157 bulbs in all 4 fixtures.
First verify the brake lights work.If you working alone you can poke a cotter pin in the back side of the brake light switch to create a closed loop or just shove a straight pin through the 2 wires. Once you have both brake lights on move the signal switch left then right and see if it turns off the relative bulb.
Test results will either point at a bad signal switch or rule it out.
Then we can continue