Go ahead and select the clip you are looking for and drag it into the Timeline. This is not the same with photos as it is with video. If the video clip is already in the Timeline just go ahead and right click on it and choose Video Effects. From here you will be given the classic video effect menu with the list of possible video effects in the left column and the video effects already applied to the clip in the right column. If you go down you end up having four main options. There are three titled Film Age, with three degrees: Old, Older, and Oldest. Depending on the age of that is indicated it will add desaturation, interference, video noise, deresolution, and other types of film degeneration that mimics older film stock. There is also Film Grain, which just adds a certain amount of appropriate film static. Each of these is meant to alter the visuals so that they end up mimicking an older film look, but you cannot change the degree to which each one does. You can use more than one, but it is really best to just use one specific age of film effect and then possibly the film grain if you must. Just go ahead and select which ever you choose, click the Add button in the center, and then the effect will head to the other column.