So as far as I can figure:
He subbed on Dalot for Sancho in order to replace Bissaka as Bissaka had been sent off. Fair enough.
Then, he subbed on Varane for VDB, even though we already had a fully manned defence and this would leave us 2 players down further up the pitch. As a result we then conceded a goal due to having too many players positioned in our own box.
Then, he subbed on Matic to replace VDB, except he'd already subbed off VDB, so instead Matic had to replace Fernandes, so then he also subbed on Lingard to replace Fernandes, except Matic was already replacing Fernandes, so Ronaldo had to come off for Lingard.
Then he subbed on Martial to replace Ronaldo, again, except as he'd already subbed Ronaldo off, he had to sub Martial on for Fred, which meant Ronaldo (now Lingard) had to go and play in Fred's position. Then Lingard, most likely due to not being a midfielder, set up the winning goal for the wrong team.
This is literally what he did.
I mean, people say he is tactically clueless or naive but I think that's wrong, as this infers that what he is doing has some kind of relation to tactics. These are the subs of someone who has no idea what is going on and ends up continuously doing things to try and correct the mess cused by the previous doing of things that they did. If he had simply done nothing at half time and wandered off to explore the sites of Bern for the second half, we'd have had significantly more chance of winning the game.
The worst thing is there'll be all kinds of threads in here and posts on twitter lambasting the players or their mentality, when actually if you just look at the above it pretty much explains what they were up against. Like asking a boxer to win a fight but his trainer is remote conntrolling one of his gloves and keeps using it to accidentally punch him in the balls.