Install problem in ios 11,3 on iphonel SE

I have made a couple of small app and use them as management with my android phone.
It also works fine to test through companion from windows 10.
I would like to try to get my little iphone SE with iOS 11.3 to work.
But it seems to be more complicated to install companion so it can be tested but I build.
Is there a good way to install the companion - ideally for “dummies”.
Best regards Eyvind from Denmark

Ps. This is a google translation. :slight_smile: