Find a place to work, where you can be alone with minimal distractions (atleast maybe some background music while you work is always a fine idea), get a clean table wide enough to accomodate all the stuff you will be utilizing (I’ll list down these stuff later on), I suggest you move the table against a corner wall since it can stop some parts from falling to the floor when you throw them accidentally because finding small parts on the floor is a real pain especially when you have no idea of the direction of where they fell. The main idea is to have a work place that is peaceful, a desk top that is clean and a work area where you can avoid the loss of those small parts, and make sure you have desk lamp as well, it’s always great to work with a spot light on.
Now what you need is to set up the table with the tools and materials you need; first of all place the gunpla box on the table, and on the far side of the table place the primary tools for plastic modelling like Side Cutter or any similar tool that allows you to cut and detach a part from the sprues, a Hobby Knife to further clean up the uneven surface marks brought along by the separation from the sprues via the sidecutter, and some optional tools like sand files, sanding sticks, color marker pens which are used to get rid of the nub marks even further.
Take your seat, concentrate on the gunpla box, grab the opportunity for some enthusiastic gaze over the illustrations and figures printed on the box. After some time you would want to open it, but be very gentle. Right now you are going to need to inspect what’s inside the box carefully. Take the contents off the box one by one, take the sprues’ plastic covers off very carefully since you wouldn’t want some stray contents to fly off because sometimes (its very rare though) some parts can get detached from their runners. Next, see the manual and look at the page where it shows all the sprues (or runners) that should be required, try to find and match with the contents of the box to make sure you’re not missing any sprues. Other contents like promotional leaflets and decal/sticker sheets you can put them away on a safe place for the mean while.
So we are set. Now grab the manual and look at the instructions, go to the page where it shows the list of runners it also shows basic instruction as well as some more information specific to the gunpla kit, if you don’t understand japanese writings then try at least to ponder on the icons shown on that page, they represent something or situations you will encounter later while working on the kit, I will overview this page and explain the icons here since I am positive that you are not so keen on continuing unless you know what these symbols mean:
Now we can begin the actual work
