Ok assuming that the passenger side door works fine opening & closing & all the gaps look good then you can use this as your refrence:
Your going to have to release the hinges enough to manouver the door into correct alignment, now it could be lift the entire door or just pull the bottom hinge out or maybee push the top in or a bit of all. its a case of trial & error here & keep playing until you find the correct alignment.

Little tip here as i mentioned above if the n/s door is fine then a quick look at the n/s will give you an idea of when the door should align i.e panel gaps.

you may have to remove the lock catch off the b post & replace it when done (door alignment in a body shop is done with catch off then fitted afterwoulds)

the side door could be either the guides or the lock not aligned correctly try the guide 1st, these are the little plastic thing on the b post that guide the door in.

Ive only done a ferw vans in the bodyshop & its been a few years now.

Good luck.

Your slider well they can be a pain first ensure the bottom runner is free of rubbish crud, dirt etc its amazing waht can be found in these which can easily throw the door offline assumings its clean and well greased moving to teh top runner ensure its running freely by closing door from inside that done and ok check both plastic runners they run on for wear chunks out of then etc then same trick as above only you will need to borrow another T5 for its side door gap, adjust to suit and bobs your auntie basically look around you many dont shut dead right my builder took 3 full days to get my T4 one working correctly and it does now

Failing all above new top and bottom runners a bolt on bolt off part that does wear depends what your van was pre you owning it if a parcel deliver type van it could very well just be badly worn