tutorial for a newbie?

[EnfanTerrible]

Hi to everyone,
I'm a totally noob and I just bought a DC SD Adapter because my Optical drive has many difficulties to read (don't know why but I put my DC 20 years ago in his original box that was perfect and now that I've tried to play some games it has a lot of difficulties to read).
I've downloaded some games from Vimm's Lair and put into the microsd with dreamshell 4.0 but many of them don't work. I'm reading here on forum and I've understand that I have to optimize the games and sometimes change some parameters before loading them so I've downloaded iso_make and had some tries but I can't understand how to do it and scripts gave me errors.
Is there a guide/how to for a total noob like me? Tried to googling around with no luck.
For example trying to extract Sega Rally seems to get errors due to spaces in file name:



Thank you for your support.