i dont understand the mechanics of Ps4 too well.maybe its the wrong place to ask,but i cant find the snapshot button/screenie.i cant even find it in options.What am i missing?
You capture videos and screenshots, livestream etc with the button opposite to the Options button, the Share button (to the top left of the touch pad).
Particularly with videos and screenshots, while you CAN set them to upload directly from gameplay, but generally you'll only save most things to edit and upload later, outside of gameplay.
Wherever you wish to upload a video, screenshot or live content, you need an account with a supported third party website, such as Youtube for videos, Twitter for screenshots, Twitch for livestreams etc to post your content to, which then has to be linked with your PSN account.
I've personally only posted videos to Youtube and while you can run them through the PS Store's free programme, Share Factory to add intros and outros, record voiceovers and set the system to upload videos at the native 1080p quality of the original captured video, but aside from once testing it, i only do direct uploads with the share button's regular upload process at its' standard 720p upload quality now, for its' slightly quicker upload speed and less fuss.
Though at the very least i still trim the footage of whatever i'm posting, as assuming you've been playing the particular game you're capturing long enough, haven't changed the setting, come across a section of the game which is blocked from capturing, such as a late game cutscenes in certain games (which is noted on screen) or captured another video in the last few minutes, by default the system captures 15 minutes of up to 700mb of footage, each time the capture video option is selected and if your internet is like most peoples' (unless you have synchronised upload and download speed), your upload speed i likely a LOT slower than your download speed, so it's best to upload the shortest videos possible...

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(Not that file size really matters for screenshots.)
(For example while my download speed is normally in the 14-16mb range and i can download a gig of data in ten minutes or less and six or more gigs in an hour, my upload speed is in the kilobyte range, taking ten to twelve minutes to upload the around 50mb, 1 minute videos i normally upload - the handful of times i've uploaded a ten minute or so video, they took one and half to two hours to upload!

.)
So while for videos i know Youtube works very well, even if you don't have an account with one of the required hosting sites, when you capture whatever you want to upload it's stored on the PS4's harddrive 'til you've done whatever you intend to do with it and manually delete it (if you ever do).
Selecting to share a particular thing will give you a list of that filetypes' supported websites, if you don't have an account with any of them, you MAY be able to create one on your PS4 or you may have to do so on a PC then return to your PS4 once you have one - it takes less than a minute to see if you can upload your particular thing to a particular site.
Once you have a linked third party account (and assuming Sony's servers aren't acting up making you relink your third party account multiple times and failing to go any further, which happens
very rarely, though if it does happen, it normally fixes itself in a hour or less as if nothing was every wrong), you can upload as much as you like to it...

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Lastly, once whatever you wanted to upload is on your desired third party site, you can come on here and link such content in threads on this site and others

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(Or in places like your signature etc.)
(If you, like me post several videos from the likes of Fifa one after the other, they'll upload one after the other... though as said, they'll likely take a while to upload, in which time you can't turn off your system without it interrupting the process, so it's best to only upload things when you've plenty of free time

.)