iPhone SE user guide

I bought an iPhone SE yesterday and would very much like to be able to have a full version of it on my computer. Can anyone tell me how to achieve this. I would be extremely grateful if this is possible. I previously had an iPhone 4 and am in the process of moving the sim card from it to my new one. I have been using a computer and phone for some time but, being 77 yrs. old, find it a little difficult to keep up with all the new things ! - so simple instructions would be greatly appreciated.