Well to make it you must make the map once your done do this:
The world
save and quit world then go to your homepage and click on worlds
pick the world and click on the edit icon
next go down and click export
edit the name if need to in the file explorer, make sure it is in downloads file, and boom you have the MC world
upload the world onto PMC
Image
add the Page Content, video, other way of download, seed, and other stuff
to get the snapshots click two keys at once, "window" and "g" getting the screen with xbox stuff
next click on capture
then click the take a snapshot icon
get as much as you like (20 = max)
after that click on "show all capture" it will take you to gallery
click on the file explorer (looks like a box)
next click all the picture you would like to use for the image gallery then move it to pictures
click on the +image on PMC
click on choose file
click on the Minecraft images then add them in
Done!
to finish it of check if it works by previewing it! if it does not work check if your on a windows 10! MAKE SURE TO CLICK ON BE MAP ON PMC!!! there are other ways of taking snapshots but if your to lazy do it the Minecraft way! ALL PMC RULES MATTER!! x<15 my age is so don't make fun if your 20! map link