Hi! Welcome to SC1! 
Have a look at my advice/guide:
You’ll see that I mentioned this:
SCHNAIL only works with Starcraft v 1.16.1, not with Starcraft Remastered. If you beat the hardest bot on SCHNAIL you are as good as a low B on the battlenet ladder, if I’m not wrong.
So, if you beat bots as good as D rank for ICCUP (ICCUP was a 3rd party server, where the best players outside of Korea would play there. Korea is the best at SC1 and they had their own private server - 3rd party - Fish server), then you can start hosting games for 1v1 melee (I don’t mean you should try ladder yet; also don’t join 1v1 UMS maps, they might be rigged). I’d try out ladder after I’d beat the best bot from SCHNAIL, because ladder has smurfs and that’s definitely going to bring your morale down if you keep losing over and over.
Here’s what the rank of the bots used to be back in September 2021 for ICCUP (currently ICCUP ranking is not shown anymore as it is dead):
https://web.archive.org/web/20210926011029/https://sscaitournament.com/index.php?action=scores
And here’s how you can check out their exact rank for ICCUP:
https://i.imgur.com/dzjcMIA.png
Here’s the overall ranking for year 2020-2021:
https://sscaitournament.com/index.php?action=2020
Some more info on ICCUP. ICCUP got closed down at the start of September 2021, as pointed out here: