how to start writing a fic???

i have so many fic ideas but i just dont have any creativity to write one. i literally only have ideas for specific scenarios or specific settings. i literally couuldn't write any intro or build up or whatever it is you need to write a fic. i can only write the scenes that i have in my head. anymore than that, my head will literally start overheating. i have tried writing a full fic but it turned into a freaking ESSAY!!! (ᵕ—ᴗ—) can someone give me tips or guide?