To replace the bulb in the 1977 Cordoba, grasp and pull the lens/cover/sleeve. The sleeve is a press on, interference fit. A slight rocking motion might be required to free it up. Don't try to twist it because the cover is keyed to the bracket for alignment.
The following image shows the sleeve in place next to the hazard flasher switch:
View attachment 2052220
The tab next to the sleeve is the alignment key.
The bulb is a 1445 with a bayonet base. After removing the sleeve, push and turn the bulb slightly counter clockwise to remove it. Install the new bulb by pressing in and turn the bulb slightly clockwise to engage it in the socket.
The following image shows the removed lens/cover/sleeve and lamp:
View attachment 2052219
Reinstall the sleeve by aligning the slot with the keyed portion of the bulb bracket and press in until it seats.
The lamp time delay relay in a 1977 B-body is located as shown in the following image:
View attachment 2052218
For more information about the lamp time delay relay itself, see the following:
Lamp Time Delay Relay