UHHH LAYOUTS ???????????????/

HELLO so this might be obvious stuff but like how do people make layouts??? like from scratch??? OR EVEN FROM A BASE??????? do you do it directly on spacehey? are there diff programs you can use?? IDK I tried googling and didnt really get anything, I know it's like coding and stuff obviously but I have sort of been wanting to make my own layout? attempt to??? IDK I made my acc yesterday and making ur own layout seems so cool but I am COMPLETELY lost XC