HTML Questions! How 2 change the logo & the colour/background of the bar thing, change footer & online logo

i wanna put my custom friend rewind logo i drew there!! i also wanna make the grey pink cuz i like pink OR LIKE A COOL PINK PATTERN

i wanna put a cool image on this section!

i wanna change this to a custom gif i made!!

as for the logo, i found the following code did technically work but it had a glitch where it made the nav bar huge and didn't work to resize, but that may have been the specific image i used.

.logo {

content:url("YOURURL");

}

to change the top bar to an image

. myspace-header .top-nav {

  background-image: url("yoururl");

  background-size: cover;

  background-repeat: no-repeat;

  background-position: center;

}

the top bar nav buttons 

.myspace-header .main-nav-wrapper {

  background-image: url("yoururl");

  background-size: cover;

  background-repeat: no-repeat;

  background-position: center;

the rest im unsure.. sorry if those dont work 'T_T