I have a group that I play with and we created a world and take turns running the sessions. I'm having issues giving my fellow players a challenge without it being a world changing event. We are running it in basic and most the characters are 10th level. Any ideas?

Hi Vorprax o/

How about some "flavor of the week" monster hunt? There arte plenty threats at level 10 without them being world-threatening events.

In the basic rules you have THESE adversaries in the 10-12 range (which would constitute a challenge for a lvl 10 party), most of them are not really world-threatening level, and you could even easily build a story around them without it being a monster hunt per-se...
Maybe you could use the Horned Devil as the main "boss" for your adventure, and build the story on intrigue and subterfuge, with the party having to investigate on strange occurrences connected to some sort of cult beginning to form around a non-specified demonic creature.
It's a pretty basic plot, but easy to develop and run, and opens up to future adventures as well: why did the Devil decide to come to the material plane and start a cult? Was he sent by someone else? Was his intent simply being worshiped, or was he to build a foothold into the region for an incoming greater evil?

See the problem is that in the town it is set in. The players set up an adventures guild to take out local monsters and issues.  Any time I offer something like that they pass it to the guild to hunt down.

Let them do that, and then come back to them with a story about a massacre of whatever they sent to deal with the issue because those guild recruits were not strong enough to handle fighting a monster of that CR level.

We are running basic and I have been trying to get use to playing in basic. So I am trying to follow all the rules and have fun. There are a lot of different rules between all the different editions.

What do you mean "running basic"?   Do you mean literally the Red Box set?  Or are you using what you feel to be accepted and understandable slang that the rest of the world is clueless about?  If so, STOP...just stop and use words that convey meaning to the world at large.

I mean the original books for dnd. The books that Gary Gygax helped make and used for his sessions. My group had them and all they want to play is it. I tried to get them to use 3rd and 4th and 5th edition but they made the entire thing into a giant crap show. So I have been reading the books and not having much luck with making a challenge or fun time for them.

Sounds like you are using First Edition?

You can't mix and match stuff between editions. I would suggest 'upgrading' to fifth edition (5e). Part of the confusion is coming from 5e having a thing called the 'Basic Rules' which are the core rules that you need to play. They are entirely free and you can find them in a variety of places, one of them on this site: Basic Rules