This can be slightly complicated. Are you talking about floppy disks or CD-ROMs?

In some cases you can just combine all the files from each of the disks into a single directory and run the installer.

In other cases, you can start by mounting a directory containing the contents of the first disk in DOSBox. Then when the game asks you for the next disk, you switch to Windows, remove the contents of the mounted directory, copy the contents of the next disk to the mounted directory, switch back to DOSBox, press CTRL-F4, and keep going.

If neither of those methods work, you will have to use disk images. You can make BIN/CUE images of CD-ROMs using ImgBurn, among other programs; you can make floppy images using RawWrite for Windows. Then you can mount all of the images simultaneously using the IMGMOUNT command in DOSBox (see the readme for examples) and press CTRL-F4 when you need to change to the next image. Note that you will need an SVN version of DOSBox to use this technique with floppy images.

The particular game was downloaded in a archive and unpacked, in it is only an install file and other files, as a matter of fact I don't see anything clearly marked as disc two! but it does ask for it. There are addons included with this game which would need to go through the same process of installing in the games folder. I think you answered my question pretty good with the switching and ctrl f4. I will give that a shot first and see how it goes. I have RawWrite in case it comes to that. Thank you for the help and your time

This would be much simpler if you owned the game, then you'd have a much simple and easy way to just have to mount your actual disc drive, and actually physically insert the discs when asked...

DOSBox mounting ISOs are for those who image their own CDs for preparation of a disc-less machine or just to ease up on that aging back and spine... not for "downloaded games" 😁

[Thread moved to DOSBox General Section]

Mat wrote:

The particular game was downloaded in a archive and unpacked

There should probably be a readme or some other text file with explicit instructions in it. Sometimes it ends with a .NFO; you can open those files with Notepad.

If there are no instructions then you should either contact the people who are running the site where you found the download, or just buy a legitimate copy from eBay. It is probably not worth the headache of trying to figure out how it was packed otherwise.