Not everyone is willing to create their own rag pulp from scratch, or purchase flax fiber premade, but you can still make homemade paper by recycling existing paper.
First you need to collect non-shiny paper. Remember that if you use printed newsprint the ink will make your paper grey. Any color in the paper will affect the eventual color of your paper. Don’t be afraid to experiment. Adding a little white vinegar to the pulp may make it whiter.
You will also need a piece of window screen, stretched on a frame, to scoop up and drain the paper pulp. And a casserole or other pan that will hold your paper pulp and allow you to scoop it up with the screen. The pan MUST be large enough for the screen to fit inside it and deep enough for you to be able to get the screen down under the pulp.
In historic papermaking felt is placed between the layers of pulp and then the stacks of pulp and paper are pressed to squeeze out the excess water. You will need white felt, or muslin, or some other colorfast fabric with a smooth surface, to put between the layers of pulp if you wish to press them. Pressing is important in order to consolidate the pulp into paper and make the surface of the paper smooth enough to use.
Some people have used a rolling pin to consolidate the pulp into a sheet of paper and smooth the surface slightly. Decorative art paper can be made by placing small colored pieces of tissue paper and/or colored fiber onto the pulp and then consolidating it. A sturdy flower press or even two pieces of smooth plywood and a stack of bricks can be used to press the pulp. Remember that if the plywood is grainy the paper will acquire that texture. Using smooth sheets of plastic inside the plywood will eliminate that problem.
Once the paper is pressed to your satisfaction you will still need to finish the drying process. Damp paper is still fragile and susceptible to mold. The paper can be laid flat and turned periodically or hung on a line, depending on how dry and sturdy it is. The paper will tend to naturally wrinkle as it dries. Ironing before it is completely dry may help a little and you can also press the paper again once it is mostly dry.
Once you have all of your equipment assembled, tear the paper up into one inch pieces and soak them in warm water to cover for about 20 minutes. Then place the soggy paper into a blender, add a little warm water and blend. Pour the paper pulp into your pan. It may take some experimentation to determine how much pulp you need in the pan. There needs to be enough water and pulp so that you can put the screen into the pan, and gather pulp on the screen in a relatively even layer. I have seen some processes in which the screen is dipped more than once in a very thin slurry of paper pulp to build up the thickness of the paper, but this seems a bit too complicated for the beginning papermaker. Experiment! As long as you get the results that you want the exact technique that you use is not important. I suggest that you reread the article on historic papermaking. The description of the screen dipping technique is very good.
Allow the layer of pulp on the screen to sit until it is mostly done dripping, place a piece of fabric or felt over the pulp and then flip the screen over so that pulp stays on the fabric. You may find it easier to flip the screen if you back the fabric with something smooth and stiff like a piece of plastic or a pan. If it is your first piece of paper you can use whatever you are going to use to press the paper to help turn the pulp out. Continue to stack the layers of fabric with pulp on it until you are ready to press the stack. Then top your stack 0f protopaper with your other piece of plywood and SQUEEZE. Press the stack for at least half an hour and then check to see how consolidated the paper is. Press more if necessary. Allow you paper to dry thoroughly before storing.
I hope that these basic instructions will inspire you to try re-cycled papermaking at home.