First you have to locate the blower motor....  Typically, there are two places that the blower motor is found. Under the glove box on the pass side of the dashboard maybe near the kick panel, or on the pass side under the hood near the firewall.  It is easy to spot once you see it because it'll be the cylindrical object on the outer most part of the heater/A/C assembly (the big black plastic looking box thing..) and it will have a electrical plug or plugs connected to it.  Now that you've found it...  you can start to remove it.  First make sure your ignition isn't on. (the unit could auto-start if your Buick has the auto-climate control feature). Then carefully remove any and all electrical plugs that are connected to the blower motor assembly. These plugs have a small tab on them that must be pulled out or pushed in in order to release the lock mech in order to disconnect it / them. Be mindful of which plug goes where if there are more than one and also how the electrical circit is routed (how the wire is ran). Next, locate the retaining screws or strap. The screws are typically found on the outer area of the blower assem. and are in a "Star Like" configuration.  If its the strap type, then you will find a strap going from one side of the blower motor to the other and crossing on the back of the blower assem.  For this type you just have to find the end that is removable and remove it.  Both ways, you will find that once the screws are off the blower comes right out.  A few notes when purchasing the replacement, make sure to "Match Up" the new one to the old one.  Look to make sure that the electrical plugs are in the same place, that they are the same type and that the screw holes or strap route  is the same. Also, some blowers don't come with the fan blade assem. so be sure not to damage the old one while your pulling it out... just in case.  And if in fact your replacement blower doesn't come with the fan, make sure you can re-install the old fan onto the new blower in the same way you took it off of the old blower (usually a self locking nut in the center of the blade assem).  The re-install is simply a reverse order of removal.  On a personal note, I would check the inside area of the heater assem. now that you have the blower out.  Hair and dirt love to find their ways into that spot and now would be the time to clean what you can out....    Have fun!!!!