Hi please tell me what thaco is should your thaco be a high number or a minus number which is the better? thanks

To Hit Armor Class 0. The lower the better. Cheers

And minus numbers are lower than 0...
(well, some people don't know that)

to hit someone you have to roll a d20 dice you have to get a number above you thac0 with the armor class of the enemy reduced (kabotls have ac 7 so if you have thac0 15 you have to get 15-7=8 )
so the lower the thac0 the better