As you already know, the major and the only reason why this seat is called the convertible is because you can have it front facing for a toddler and rear facing for an infant. There is a black handle bar underneath the base. Simply lift it to recline the car seat.
Britax Boulevard allows your child to be rear facing from five to around 30 pounds. You can turn them forward facing when they have reached age of one and 20 pounds.
Next, I will explain to you how to properly install a Britax Boulevard baby car seat. First, you must recline the seat by pulling recline handle on the bottom front of the car seat. If you are using noodles to help with the angle remember to make sure the baby seat is directly on top of the noodles. Britax uses push on LATCH connectors. If you are using them, first attach the LATCH connector to the lower anker by pushing it on firmly and listening firm click. You must repeat the same process for the other side of the seat. Next, working on one side of the seat at the time press down on the side of the seat and pull on the LATCH strap close to the LATCH adjuster; and off course, you must repeat this process until the LATCH belt is tight. After one side is done, do the same on the other side of the seat. By pulling on the unpadded straps close to the adjuster you get more and more leverage and that makes it easier to get the Britax Boulevard tight. Now you only have to adjust the convertible car seat as needed, so that is straight. But don’t forget to check for tightness at the belt path. Remember, it should move less than one inch when you tog side to side and front to back. Also, it is very important to check for the reclining angle. You can use a paper triangle for this. The baby seat should be installed at a 45% angle for a newborn or very young infant. The movement at the top of a car seat is called rebound. That is perfectly normal movement and it happens on rear facing baby seats since it is nothing holding that part of the seat. After installing the seat it is recommended that you check everything one more time.

There are four strap positions on this car seat. When your baby is rear facing you have their shoulders just at or slightly above the harness. When they are forward facing you can have it just at or slightly bellow the harness.
Although Britax Boulevard handles all their requirements needed for a convertible seat most people still tend to start off with Britax companion or some other infant car seat. This allows you to be much more mobile.