Before using psds you must have them, so download some. You also must have Photoshop.
Step 1: open the gif that you want to put the psd and the psd on Photoshop.
Step 2: now there’s two pages open(the gif page, and the psd page), just one is showing, ‘cause the other one is hidden. To see them both you have to click on the ‘square’(it’s on the toolbar), click on it ‘till it shows two ‘squares’. And on Photoshop cs5 just click on arrange documents on the top.
Step 3: you can see both pages now. It looks like this: Exemple with the gif and the psd that i chose.
Open the layers window (click on the gif and the layers will be about it). Click on the last layer of the gif(example: the gif has 7 layers, click on the 7th layer).
Step 4: in the layers window(now the psd window, click on the psd and the data will be about it-the layers are always about the picture/gif/psd you clicked at last) there’s something like a ‘file folder’, click on it and drag it ‘till the gif that you want to put the psd(p.s.: the name next to the file folder does not change anything). In this case, drag it ‘till Niall’s gif.
Step 5(last one): when you have dragged it, the gif will have new colours, the psd colours! Put a name on it and save! You also can put more than one psd! To put a name click on the ‘T’ in the toolbar, and remember that to make the name/psd stay in every single frame, you must have selected the last layer. And now it’s looking like this: