It is advisable to put plywood subflooring before installing linoleum. It will make the surface even and it will provide a surface that will adhere easily to the linoleum.
First of all, make sure that you remove all the existing flooring. Clean the floor and measure the floor area. Then check if the surface is even. If there are uneven surfaces make sure to use a leveling product. Apply the plywood sub flooring. Make sure that the surface is clean and then you can put on the plywood. You also have to remember that you will need to staple the adjacent plywood together at the seams using a pneumatic stapler to ensure tight seams for a sturdier base. After you make the subflooring, determine the measurement of the room and divide the floor space into four quadrants. This will ensure that you can work in an organized manner, hence, lessening errors. Also, this measurement will help you know how many tiles you'll need and so that you can prepare tiles that will go on the sides, if you need to cut them to fit. Clean the plywood surface before starting. Be sure that no dust or any dirt will be left so that the linoleum can stick well on the subfloor.