When I got back from Viet Nam and the surrounding countries, and the next few years hunting and backpacking I realized that to show my slides I had to use a projector and screen and I basically quit taking slides until I bought my first DSLR and then, I found several ways to copy slides to my computer. One of the ways was a slide copier mounted to my camera (one at a time). Then I downloaded my pics from the camera to the computer. After 100's of slides , I saw advertised, the slide copiers that hooked up to the computer and you could copy slides or photos directly to the computer and edit them first on the box, and later on the computer. There was a slide holder that held 4 slides at at a time or one photograph at a time. Most of the slides were taken in 1967 thru 1970 so were in pretty rough shape but I was able to save most of them and of course when I quit using my Asahi Pentax. SLR & also quit copying slides. I still have hundreds of slides of the rest of the years to copy.
The slide copier I have. I bought from Adorama in the 90's and I be trying it again soon (for approx. 150 slides)
My copier is The Image Box Plus and I see that there is one similar still on google search. I paid around $100.00 for it.
I do still have the single slide copier that attaches to your camera if I can find it---I see those are still available also. Attached are two pics taken in Ubon Thailand in 1968 & copied from the slides approx 45 years later.
The box I use attaches to the computer via USB cord. Also, my older brother copied hundreds of Yellowstone Park slides on his flatbed computer that came out real good. But, I think there are some good comercial places that do slides much faster and some probably better!