...Whenever I inserted images, they always come to foreground and block everything.
Hello. Regarding the inserted images thing:
After having inserted an Image, we can select it and change its "Draw Order", via the "Send to Back" command. Then it will appear in the view behind everything previously drawn and newly drawn (assuming all the Layers' Layer_Order value is set to the default 0).
Another-- and perhaps better-- alternative:
Create a New Layer, specifically to assign inserted Images onto. Name that Layer something like "Images".
In the Layers Palette/Layer_Order column, give that Layer Order a value of 0.
the other Layers a higher Layer Order value; a value of 1 will suffice*, but in a complex drawing, varying values might serve you well.
*Tip: If you have a lot of Layers, you can utilize the universal Windows method of holding down the CTRL or SHIFT keys to make multiple Layers selection at once, then enter something like 1 in that Layer_Order column/cell for just one Layer (but not the "Images" Layer), and that 1 value will be assigned to all the selected Layers.