Grammar check    If I were to write about the history of my family, I have to do it by following three steps. Which are finding, evaluating and interpreting sources. Firstly, to find sources I could ask my grandparents or talk to old people in family as they might know a lot more than others as they are older. To verify what they said I could find records of my family if there's one or take a look at old pictures for verification and further information as well. After I've found the sources secondly I have to evaluate them. To do that I would compare different people's stories with the sources I've got about my family, especially with people who have  the same background as my family. I could also ask them again for verification. And lastly it's time for the interpretation of the sources. To interpret them  I would think about what I've learned from steps 1 and 2. I could ask elder people as well for their thoughts and experience on it as I think they might know much better than me.

I made some corrections:

If I was to write about the history of my family, I have to do it by following these three steps, which are finding, evaluating, and interpreting sources. To find the information needed, I could ask my grandparents or talk to grown-up people in the family as they might know a lot more than others as they are older. To verify what they answered,  I could find records of my family if there's one or take a look at old pictures for verification and further information as well. After I found the resources,  I have to evaluate them. To evaluate,  I would compare different people's stories with the sources I got around my family, especially with people who have the same background as my family. I could also ask them again for them to verify. Lastly, it's time for the interpretation of the sources. To interpret, I would think about what I've learned from steps 1 and 2. I could ask grown-ups for their thoughts and experience on it as they might know much better than me.

Explanation: