Open Photoshop
Go to File > Open and select your images or video frames
Go to Window > Timeline
Click Create Frame Animation
Click the menu in the Timeline panel and choose Make Frames From Layers if needed
Arrange the frames in the correct order
Set the duration for each frame
Set looping to Forever if desired
Preview the animation using the play button
Go to File > Export > Save for Web (Legacy)
Choose GIF as the format
Adjust color, dither, and size settings if needed
Click Save
Choose a file name and location
Click Save again