What a great find and both locomotives appear to be in great shape. The 681 was made between 1950 and 1953. The 208 was made in 1958-1959. Both of these locomotives are, probably, older than you. Before you do anything, they should be cleaned and oiled. Old grease can be like cement and has to be scraped off and old oil will be a sludge. Both locomotives come apart easily with no special tools and plenty of parts are still available, although you shouldn't need any. You can clean the metal parts with a solvent such as naptha. Do not get any solvent on the plastic parts or the motors. You will some grease for the gears and a light oil for axles and bearings. Since you are new to this, see if there is a hobby shop nearby, I'm pretty sure they can help you.
Merry Christmas
