Hello, i hope you'll have some fun time with games on the Atari ST.
About searching and downloading interesting titles:
I'd say you should look for titles which seem interesting to you on Atarimania (like browsing by games category) or Atari Legend ( https://www.atarilegend.com/
You can also try the "favorites" lists here, plenty of good recommendations: viewtopic.php?f=3&t=611
And then websites like Ataricrypt: http://ataricrypt.blogspot.com/
Or The Joy of Sticks: http://thejoyofsticks.com/
Or videos by "Gears of Games" and other ST retro-reviewers on Youtube.
Also a great top 50 here: https://thejoyofsticks.wordpress.com/th ... rvey-2008/
Then for downloading a game based on his name, with the objective of putting it on a real floppy, you could check the TOSEC collections.
You'll mostly find games as .MSA or .ST in there.
This engine searches on various sources (including TOSEC archive hosted on archive.org) : http://www.oldgamesfinder.com/?m=-15
Also some people have repackaged games recently. And those are mostly available as files (as the main goal of these repackages was to run those from hard drives).http://atari.8bitchip.info/aon1.phphttp://d-bug.mooo.com/http://www.klapauzius.net/Old_Games.html
If the repackaged game fits 720ko, you can format a standard PC 720ko disk and copy the game files on it. It will work on the ST (and with 1mo of RAM, as you got a 1040, there should be no memory problem for running it from the ST desktop, for most titles).
For putting other games on disks, it's quite tricky these days.
Most regular ST users have a "virtual disk" hardware solution, either replacing the floppy drive, or the hard drive with SDcard based adapters.
But if you want to go the real floppy way, i'd say it's better to find games in .ST or .MSA format.
Ppera got a PC software which works with real internal floppy drive, but it requires windows: http://atari.8bitchip.info/floimgd.php
There are also some DOS software for this listed here (but i remember having hard time to wirte back to ST floppies with those, back on DOS PC times): http://www.atari-wiki.com/?title=Disk-Imagers
Also an interesting tutorial here: http://www.tehkella.net/retro/?p=361
It describes the other disk image split solution at the end, writing actual images to disk with the real ST drive.
Most games that can be copied are cracked games. So it's not the exact original game disks. Most of the time you'll have an additional cracker intro screen, sometimes an optional trainer mode as well.
And many games have been packaged in compilations (several games on a floppy), then also repacked for this, sometimes with some original game data removed (like a large intro animation).
Sometimes (rare cases i'd say) the crack is bad, so the game won't be finish-able.(maybe you have figured most of what i wrote by yourself, but as i typed, i tried to be comprehensible by any newcomer, not sure it is though )