got this of a web site:

1.) Stack Up
In this example the element stacks up on one side of the door (where the door handle is located). R1 is in the prone position, R2 is covering R1 and the opposite side of the door (i.e hallway). The element leader is between the two teams, and also covers the hallway. B1 covers the right hand side of the stack, while B2 is guarding the rear (i.e. hallway).

2.) Open the door, deploy flashbang
While R2 is covering the door, R1 (still in the prone position) opens the door, weapon at the ready. If no immediate threat is encounterd, R2 throws in a flashbang.

3.) The fatal funnel
R1 enters first, an covers the right half of the room. R2 is following immediately and covers the left side of the room. B1 and B2 are covering from the outside, getting ready to enter behind RT. Clear the doorway right away!

4.) Clearing the room
R1 goes to the right far corner, pointing his weapon to the opposite corner. R2 clears to the near left corner, pointing his waepon to the opposite wall. The far left corner is called "No-Man's-Land". Never point your weapon to the direction of a teammember!

5.) Secure!
R1 goes to the right far corner, pointing his weapon to "No-Man's-Land". R2 clears to the near left corner, pointing his waepon to "No-Man's-Land". Never point your weapon to the direction of a teammember!
B1 follows and goes to the near right corner, followed by B2 who stays near the door and covers it. B1 will cover upper areas (like balconys etc.), if there are any.
The element leader is the last one who enters the room. He then may issue further orders.