Just to chip in on this subject, I’ve done a lot of work on my family history (its a little more complicated than some, as it includes Italian and German heritage as well as English, Irish and Scots). I would recommend Ancestry.com as others have. Its not cheap with a monthly subscription, but as well as giving you a repository for your existing records it gives you access to a vast amount of data. A word of warning however, as others have pointed out, don’t believe what you see in other people’s family trees without seeing documentary evidence. Unfortunately, a lot of people don’t take care to check their facts.
On the plus side by using Ancestry.com I was able to locate a cousin of mine in Canada who had been lost to the family since the early 1960’s and reunite him with his half-sister in Norway as well as taking him to Dublin to meet many of his Irish cousins that he didn’t know he had. Another plus for me was to find that my family in Leipzig attended their local church where a young lad was making a name for himself tickling the ivories – by the name of J.S.Bach!
On a more serious note, my grandfather, while serving in the RAMC during WW1, was hit in the face by shrapnel while working as a stretcher bearer in no-man’s land resulting in an horrific injury. As a result, he became a patient of Sir Harold Gillies, a pioneer of plastic surgery. https://allthatsinteresting.com/harold-gillies#20
I mention this to follow on from the PTSD already mentioned. Again through Ancestry.com, I was contacted by a PHd student doing her doctorate on the psychological impact of the injuries these men suffered. I learned so much about my grandfather’s reclusive behaviour from her interviews with other families.
Graham