Help me first time DM

Hi, i am sorry english isnt my first language but i am trying my best. Its my first time DM next month and i do have a problem with my story. i have ideas from some research and from the masterguide but i dont know how to put it together in a good story. i would be more then grateful to get some help from the community.

Here are my ideas:

-Kingdom with a good queen who has power of to gods who created this kindom to have a save place and hide from the god war

-queen is young and has a dragon who helps her with tasks

-evil god has found a hole in the border and is now trying to distroy the kingdom

-chaptured the dragon who works now for the evil god

-citizens turning into monsters and magic creatures are losing there powers

-players have to defeat the evil god, heal the dragon and help the good god to get her powers back

-an assisin would be great

-and the evil god hides himself turning into a child who sometimes followes the group or is in the same places

-evil god has powers: anipulate things, changing places, chance animals.....

if you have ideas for iteams, more lore, story, or something else i would love to hear them, thank you all <3