New to being a dm and need help!!

uh hi everyone, my name is voidstar and I'm coming onto here to see if i can get any help with being a new Dm so i would appreciate the help!

its from a game book i got from fools gold by dingo doodle, this is their videos please check them out!!

https://www.youtube.com/watch?v=1H-1WJtuzPg&list=PLFOaJWATTt_A7thZA9WFGEpZRC9CBjkWY

they inspired me to may my plot for my game

so here's the plot i have for my game or so far:

there is a kingdom in a forgotten wasteland, mutated monsters left and right and the pres-ten walls of the fore-claimers, where though who come of age go to explore the world in order to put everything back to normal to set the world balance, but the party will come across a town with other adventures, but when the party finds out they were experimenting with the other children that came there, they try to flee but when all hope is lost they were saved by a little lamb and the lamb explains that to in order to fully put the world back together they have to find relics

although I'm not sure how to do the improve much so i might need some help if you guys can help me that would be great