I was using the windows beta version of a program called WXtoIMG available in the downloads tab on
this site. In conjunction with that program, I was using the HDSDR Smart (a $20 SDR receiver) connected to an external antenna (at that time, the vertical dipole I use to receive FM music broadcasts). To pipe the audio from the SDR program into the WXtoIMG program (both programs allowing audio source and output to be selected in the options settings), I used a free utility called VB audio cable (a virtual audio cable software available
here). There is a youtube tutorial (the one that got me from knowing nothing about it to receiving the images
here, which covers everything I just mentioned). There seems to only be 3 satellites currently in use, but there are plenty of passes one can catch. The WXtoIMG program, once installed, has an option to "update keplars" which goes online and loads the satellite pass-over times so you can set the program up to record at the proper time if you are not around when it goes over. I used the wrong antenna and would recommend a circularly polarized antenna with a broad pattern. The frequencies of interest are in the 137MHz VHF range.
As for FT8, I have not used it yet and have no experience with it, however, I have used a program called FLDIGI which is a digital radio program that can use a computer sound card to interface with the radio. I have used that program with a digital mode called hellscriber and also decoding CW (because I am really slow at it), but it contains many modes that are built in (although I don't recall FT8 being in there). All one needs to do is connect the sound card to the radio. Some radios are harder to connect than others, for instance, my Uniden Washington 11m CB. I had to do a bit of level matching so the sound card output didn't over drive the radio's mic jack and that the radio didn't distort the computer's line-in jack. I believe there is an option in the program that can key the radio if you have the interface hardware or soldering iron skills necessary, although I always just held the key when the PC was talking
The audio level matching can be done with resistors or audio transformers, but the latter is much cleaner if you have the parts available. I wish I could give you details on getting FT8 set up, unfortunately, the majority of my experience is with AM, SSB, and FM analog, but very little with digital modes. I am a beast at tuning antennas and making electrons wiggle in an antenna from afar, but I am just starting to get my digital toes wet.
When the family that is here visiting leaves on Wednesday, I will watch a few videos and see if I can find some easy to follow tutorials for you and perhaps try it myself.