Problem #1: “Please help me to understand this effect (from day to night tutorial).”

The main idea in this effect is to make the original picture as dark as you can. Try to do it using the bottom slider in Levels (Image – Adjustments). Use the Dodge Tool to make the light effect. I think that it should help, just follow carefully the instructions here and in the tutorial and everything will be OK.

Problem #2: “When I copy from Word or text and paste it in Photoshop, the background color of Word also pastes on there. I am also trying copy table from Msword but I could not do it.”

This should help you: Copy the text itself, go to Photoshop, press the “T” button,see here the hot keys of Photoshop [link], click on the area you want to add your text and then paste your text. You can’t insert a table from Msword.

Problem #3: “I’d like to know wich font you have used on the Post-it psd.”

It is called “Journal Font’, download it here [link].