Can you help me to correct/by correcting this, please? It is very important.

3. Conclusion
  At the beginning of my research work, I set a goal to work - to explore the past of the village. From the analysis of historical material, I found out determined the major events that have affected the history of the village. I learned about the causes of the rise and fall of Kholmogory.
The practical significance of this work lies in the fact that the collected materials can be used by students and teachers for additional classes on the history of his their native land. (this sentence is fine, apart from the pronoun)
Thus, the objectives of the research are addressed, the goal is reached, and the problem is clearly stated/the mystery is cleared? put forward the problem clear. this phrase is unclear or ambiguous - what is the 'problem'?

Can you help me to correct, please? It is very important.

3. Conclusion
  At the beginning of my research work, I set a goal to work - to explore the past of the village. In the analysis of the historical material I found out the major events that have affected the history of the village. I learned about the causes of the rise and fall of Kholmogor.
The practical significance of this work lies in the fact that the collected materials can be used by students and teachers for additional classes on the history of his their native land.
Thus, the objectives of research addressed, the goal is reached, put forward the problem clear.