I’ve got a single speed k1 wide chain I want to put on my multispeed bike (lectric 3.0 ebike).

I’m a newbie, not sure of what info on the bike might be relevant but it’s a modern, 7 speed, freewheel.

I’ve messed this up before. I tried this chain on a different bike when converting it but I kept skipping.

Sounds like I need better fitting cogs? Do I need “wide” ones? Crankset and rear cog? Possible better fitting chain tensioner too? Shopping around, I’m not seeing much a difference in sizing for these parts.

Any tips appreciated