Last Thursday, we had a lot of snow.I took time off (do you mean "set it as your day off?) on Friday and I went climbing a mountain which is located in at the back of my house.
Correction:  I set Friday as my day off and went climbing on a mountain which is located at the back of my house.
Because I it snowed heavily I attached climbing irons to my boots and then I went climbing. First of all, Footstepsound on the snow in was very good. (You can also say, "Hearing my footsteps on the snow was very good.")
As I expected, the mountain was covered with white snow and trees were covered with snow. (To shorten it, you can also say, " As I expected, the mountain together with its trees was covered with white snow.")
I could see excellent views of the mountain and I took many pictures
I couldn't help it but I really admire the snow-scene.
I think that climbing of this time will live for a long time in my memory. (You can also say, " Such climbing experience of mine will be included in my long-term memory. ")

Thank you for doing your homework! It's job well done! =)

-Teacher Marian