Small hole in your tyre? Sealant will sort it. Large hole in your tyre? Better use a tubeless repair kit! 

This tubeless tyre repair kit makes the job easy. Simply insert a tyre plug into the hole and inflate your tyre. Voila, you're back riding.

If you've got a massive hole/slash in your tyre these might not do the trick. If you're in this situation consider a Rema Tip Top Tubeless Tyre Patch Kit, it will almost always sort it!