I finally found a computer I can type on. First a little history to give you perspective. Up until ~1880 photography was difficult and generally not done by hobbyists. Lenses were expensive and the common process was "wet plate," aka collodion. It was very inconvenient and a lot of work. Around 1880 we went from wet plates to dry plate. Basically the same emulsion but instead of being water based (which dried quickly--not good) the emulsion was gelatin based. Plates were sold pre-made and didn't have to be processed immediately after exposing. MUCH more convenient! This quickly caused a boon in photography as a hobby. By the 1890s there were a lot of companies making dry plates, lenses, and cameras for amateur photographers. Rochester Camera was eventually bought out by Kodak around 1912 (I think.)
Lenses. Up until about 1890 there were basically three kinds of lenses: achromatic doublets (2 element, cheap), Petzval (4 element, expensive), and rapid rectilinear (4 element, mid priced.) After 1890 Zeiss invented a new kind of glass and new lens designs became possible, such as the Protar and Tessar. These were "anastigmat" lenses and very expensive at the time. Most likely your camera has either an achromatic doublet (the cheap "kit" lens) or a rapid rectilinear. You can tell by unscrewing the element group(s) from the lens. One group = achromatic doublet, two = rapid rectilinear. Most likely it will be a rectilinear lens on a Premo as these were a higher end camera. Next, look at the shutter. They were pneumatic at this time. They ran on air pressure created by a piston inside the cylinder. Some were single cylinder, some were "double pumpers." If you can unscrew the cap from the bottom of the cylinder you can carefully clean it out with a cotton swab. Do NOT lubricate the cylinder. The pistons are generally leather and lube will cause them to swell. These shutters are somewhat inaccurate. Top speed is generally either 1/50s or 1/100s. Emulsions at the time were slow--ISO 10. Next is the aperture on the lens. In the 1890s the most common was the "wheel" or "rotary" stop. There was a thin disc in the side of the lens barrel. In that disc were holes that rotated into place. Each hole is twice (or half) as big as the one next to it. Apertures ran something like f8/f11/f16/f22/f32--i.e. doubled the amount of light. The other type of aperture was the iris, like we use today. These became common after ~1900 when the tiny parts could be mass produced. Look at the aperture scale. At that time there was no standard scale. Most American lenses used the "U.S." scale--Uniform System. It is different from what we have today. On the U.S. scale, it's f16 equals modern f16, but there will be no f11--next step will be f8. That is what we now call f11. Start with f16 and then calculate up and down a stop to convert it to modern equivalent. If your lens doesn't say what it is wide open (likely something like f8,) you can calculate by focusing the lens on something over 100 ft. away, measure distance from the back of camera to the middle of the lens, and divide by the internal diameter of the lens barrel. (Not exact but close enough.)
Holders. In the early years (pre 1920-ish) serious photographers did not use film in large format cameras. It was floppy and there would be out of focus areas. Almost certainly any photographer buying a Premo would use dry plates (glass,) not film. If your holders are original to the camera they are probably plate holders. How to tell? Open one up and look at the sides. If there is only one groove--for the dark slide to go in, it's a dry plate holder. If there is a second groove it's a film holder. You can buy "film sheaths" to convert a plate holder to use film (ebay). There were several similar sized formats in use in the 1890s: 4.75x6.25 inch half plate, 5x7 in., and 6x8.5 in. full plate. Measure the dimensions of the ground glass on the camera back to tell what yours is. Most likely it is 5x7 since this is an American camera. Since you provided no photo I can't tell if you have the modern designed holders or the older "book" style.
Bellows. Take the back off the camera, and in a darkened room run a small flashlight inside the extended bellows. You are looking for light coming through--especially in the corners. If you see no light the bellows are light tight.
To focus the camera is different from modern lenses (which have a viewing shutter.) On your lens, set it to "T" which is "Time." Shutter will stay open until you push it again. (Shutter will likely be marked: T, B, I. T=time, b=bulb, I=instant and is the shutter speeds.) Focus the lens while shutter is open (duh!), press the shutter lever again to close it, stop the lens down, set your shutter speed, insert film holder, remove dark slide, trip the shutter, REPLACE DARK SLIDE backwards to show you've exposed that sheet, remove holder.
If you want to know more, let me know. If you want me to walk you through using the camera, you can PM me and we can do it over the phone as you handle the camera. I own and use a 1905 Century Camera, a 5x7 Gundlach Korona from 1925, and a Watson & Son half plate camera (English) from 1880s. I regularly shoot a 4x5 with antique lenses.
Kent in SD